Confiabilidade e Validade ABAS-3

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5
Reliability and Validity
This chapter presents research supporting the reliability and validity of the 
ABAS-3. The analyses discussed in this chapter are based on both standard-
ization and clinical samples. Psychometric information is presented for all 
five ABAS-3 forms.
Reliability
Reliability refers to the consistency, stability, and 
predictability of test scores. Reliability coefficients 
capture the extent to which the scores are dependable 
and relatively free from error. Adequate reliability is 
a requirement for clinical application of test scores. 
This section describes six approaches to estimating 
the reliability of the ABAS-3: internal consistency, 
standard error of measurement, test–retest reliability, 
interrater reliability (two respondents rate an individ-
ual using the same form), cross-form consistency (two 
respondents rate an individual using two different 
forms), and alternate-forms reliability (one respon-
dent rates an individual using two different forms).
Internal Consistency
Internal consistency refers to the idea that all items in 
a test or scale consistently measure the same ability 
or trait. In an internally consistent test, correlation 
coefficients reflect a strong relationship among scores 
derived from individual items or subsets of items, 
within a test, following a single administration (Amer-
ican Education Research Association et al., 2014). For 
the ABAS-3, the internal consistency reliability was 
estimated using coefficient alpha, and the results are 
presented in Tables 5.1 through 5.6 for each of the 
standardization samples, corresponding to each of 
the ABAS-3 forms. Additionally, mixed clinical groups 
are presented for each form in Table 5.7.
The reliability coefficients for the GAC were consis-
tent across the six standardization samples, ranging 
from 0.96 to 0.99. Reliability coefficient ranges of the 
adaptive domains were 0.90–0.98 (Teacher/Daycare 
Provider), 0.93–0.99 (Teacher), 0.85–0.98 (Parent/
Primary Caregiver), 0.94–0.99 (Parent), 0.94–0.99 
(Adult self-report), and 0.96–0.99 (Adult rated by oth-
ers). Reliability coefficient ranges of the adaptive skill 
areas were 0.72–0.97 (Teacher/Daycare Provider), 
0.82–0.99 (Teacher), 0.76–0.97 (Parent/Primary 
Caregiver), 0.81–0.99 (Parent), 0.80–0.99 (Adult self-
report), and 0.82–0.99 (Adult rated by others). Reli-
ability coefficients of the sample with mixed clinical 
diagnoses were 0.99 for the GAC, 0.96 to 0.99 for the 
adaptive domains, and 0.91 to 0.98 for the adaptive 
skill areas.
68 ABAS-3 Chapter 5 Reliability and Validity
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ABAS-3 69Reliability
Ta
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 5
.2
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stdeal with whether the test measures the constructs 
it purports to measure. The practical components 
of validity concern the clinically relevant informa-
tion that can be inferred from test scores. To address 
these issues, the following section presents evidence 
regarding the item content, response process, internal 
structure, internal consistency, age group differences, 
intercorrelations among the adaptive skill areas, 
factor structure, correlations with other variables, 
and ability of ABAS-3 scores to differentiate among 
groups expected to vary in their levels of adaptive 
functioning.
Item Content
The theoretical basis of the ABAS-3 derives in part 
from the AAMR (2002), which asserts that 10 adaptive 
skill areas (Communication, Community Use, Func-
tional Academics, Health and Safety, Home or School 
Living, Leisure, Self-Care, Self-Direction, Social, and 
Work), grouped into three broad domains of adaptive 
behavior (Conceptual, Social, and Practical), consti-
tute the core of successful, independent functioning. 
The ABAS-3 items in each of the adaptive skill areas 
reflect universally important adaptive skills. These 
skills are not specific to any single culture; rather, 
they support daily functioning for individuals who 
may differ by age, gender, race/ethnicity, social status, 
and other demographic characteristics. The broad 
domains of the ABAS-3 continue to reflect definitions 
of adaptive behavior found in the latest editions of 
the AAIDD (2010) and DSM-5 (APA, 2013).
90 ABAS-3 Chapter 5 Reliability and Validity
The ABAS-3 items are based on those of the ABAS-II, 
the full development of which is detailed in the 
ABAS-II manual (Harrison & Oakland, 2003). Briefly, 
the authors created an initial item pool based on 
a comprehensive literature review of adaptive and 
developmental skills in children, youth, and adults. 
This item pool was refined and reduced through a 
series of field studies and expert-review phases. The 
final item set was standardized and published in 
the ABAS-II infant/preschool, school-age, and adult 
forms. Chapter 4 of this manual describes the further 
development of these items during the ABAS-3 revi-
sion process.
Response Process
A primary purpose of the ABAS-3 is to accurately 
describe the degree to which individuals display 
developmentally appropriate adaptive skills. The 
ABAS-3 uses a four-point item response scale that 
allows respondents to indicate whether skills are 
present or absent (ability), and the frequency (never, 
sometimes, or always) of their display. Aside from 
minor formatting adjustments to the response col-
umns (e.g., “ability” and “frequency” are more clearly 
labeled), the only modification to the ABAS-II (Har-
rison & Oakland, 2003) response process, which was 
designed to meet accepted standards (e.g., Kamphaus 
& Frick, 2010), is the deletion of the “Comments” 
column at the far right of the response area. This 
column was deleted based on feedback from profes-
sionals using the ABAS-II that it was rarely used and 
added unnecessary visual complexity to the area. 
Respondents still have the option to make any needed 
comments in the “Comments” section of the rating 
form. During ABAS-3 standardization, respondents 
were asked to comment on the ease of completing 
the rating forms. Respondents indicated that the item 
response scale is easy to use and the response options 
are clear.
Internal Structure
Evidence of a test’s internal structure is found in the 
degree to which relationships among test items con-
form to the constructs on which score interpretations 
are based (American Education Research Associa-
tion, et al., 2014). The AAMR (2002), AAIDD (2010), 
and DSM-IV-TR and DSM-5 (APA, 2013) provided 
the internal theoretical structure of the ABAS-3 by 
defining adaptive skill areas; domains of Conceptual, 
Social, and Practical adaptive functioning; and over-
all adaptive behavior.
Consistent with this theoretical structure, the ABAS-3 
items comprise 10 adaptive skill areas, all of which 
are expected to be internally consistent and sensitive 
to age differences. Furthermore, the adaptive skill 
areas are expected to share common variance, yet 
also be demonstrably independent of one another. 
Collectively, these adaptive skill areas form two 
additional levels of structure: the Conceptual, Social, 
and Practical domains of adaptive functioning, as 
well as an overall construct of adaptive behavior (the 
GAC). The GAC, adaptive domains, and adaptive skill 
areas all play an important role in understanding 
the adaptive functioning of individuals with intellec-
tual disability. These relationships are described in 
greater detail below.
Internal Consistency
Internal consistency refers to relationships among 
scores derived from individual items or subsets of 
items within a test following a single administration 
of the test. All ABAS-3 scores demonstrate acceptable 
levels of internal consistency, as described previously 
in the reliability section of this chapter.
Age Group Differences
Adaptive skills are acquired during the course of 
an individual’s development and are expected to 
vary with age. For example, many adaptive skills are 
acquired early in life (e.g., tying one’s shoes), while 
others are acquired later in life (e.g., paying bills). 
Many adaptive skills reach a plateau of development 
before adulthood. Unlike children, therefore, adults 
generally do not display significant increases in 
adaptive skills as they become older. However, among 
children and adolescents, differences on the various 
items can be translated into age differences on each 
of the adaptive skill areas.
ABAS-3 items are sensitive to age differences (i.e., 
persons who are older tend to display adaptive behav-
iors more frequently than those who are younger). 
For example, on the Teacher Form (Table A.12), a 
raw score of 48 on Communication is equivalent to 
the average performance of children ages 6 years, 
0 months to 6 years, 3 months. A raw score of 58 on 
Communication is equivalent to the average perfor-
mance of children ages 9 years, 4 months to 9 years, 
7 months. A raw score of 62 on Communication is 
equivalent to the average performance of children 
12 years, 8 months to 12 years, 11 months. All items in 
each of the adaptive skill areas display age differences.
ABAS-3 91Validity
Intercorrelations Among the Adaptive 
Skill Areas
The theoretical structure of the ABAS-3 suggests that 
the adaptive skill areas, considered together, have 
both shared and unique variance, and thus should 
intercorrelate at moderate levels. The adaptive skill 
areas should in turn show stronger associations with 
the GAC and their respective adaptive domains than 
with each other. Scale intercorrelations were calcu-
lated for the adaptive skill areas, adaptive domains, 
and GAC for each ABAS-3 form; this was done using 
the scaled scores and standard scores from the stan-
dardization sample, the demographic characteristics 
of which were previously described in Chapter 4. 
Tables 5.25 through 5.30 present scale intercorrela-
tions for each of the standardization samples, corre-
sponding to each of the ABAS-3 forms.
Table 5.25 presents the scale intercorrelations for the 
Parent/Primary Caregiver Form. The average inter-
correlation between adaptive skill area scaled scores 
is .60. The average corrected correlation between 
adaptive skill area and adaptive domain scores is .79; 
between adaptive skill area and GAC scores, it is .76. 
The average corrected correlation between adaptive 
domain scores is .79; between adaptive domain and 
GAC scores, it is .87.
Table 5.26 presents the scale intercorrelations for the 
Parent Form. The average intercorrelation between 
adaptive skill area scaled scores is .62. The average 
corrected correlation between adaptive skill area and 
adaptive domain scores is .82; between adaptive skill 
area and GAC scores, it is .78. The average corrected 
correlation between adaptive domainscores is .80; 
between adaptive domain and GAC scores, it is .88.
Table 5.27 presents the scale intercorrelations for the 
Teacher/Daycare Provider Form. The average inter-
correlation between adaptive skill area scaled scores 
is .61. The average corrected correlation between 
adaptive skill area and adaptive domain scores is .83; 
between adaptive skill area and GAC scores, it is .77. 
The average corrected correlation between adaptive 
domain scores is .80; between adaptive domain and 
GAC scores, it is .86.
Table 5.28 presents the scale intercorrelations for the 
Teacher Form. The average intercorrelation between 
adaptive skill area scaled scores is .62. The average 
corrected correlation between adaptive skill area and 
adaptive domain scores is .81; between adaptive skill 
area and GAC scores, it is .78. The average corrected 
correlation between adaptive domain scores is .79; 
between adaptive domain and GAC scores, it is .86.
Table 5.29 presents the scale intercorrelations for 
the Adult Form (self-report). The average intercor-
relation between adaptive skill area scaled scores 
is .60. The average corrected correlation between 
adaptive skill area and adaptive domain scores is .80; 
between adaptive skill area and GAC scores, it is .78. 
The average corrected correlation between adaptive 
domain scores is .86; between adaptive domain and 
GAC scores, it is .89. The intercorrelation between 
GAC scores with and without Work is .98.
Table 5.30 presents the scale intercorrelations for the 
Adult Form (rated by others, such as spouse, sibling, 
caregiver, and so forth). The average intercorrela-
tion between adaptive skill area scaled scores is .57. 
The average corrected correlation between adap-
tive skill area and adaptive domain scores is .78; 
between adaptive skill area and GAC scores, it is .75. 
The average corrected correlation between adaptive 
domain scores is .82; between adaptive domain and 
GAC scores, it is .86. The intercorrelation between 
GAC scores with and without Work is .97.
Collectively, as expected, adaptive skill area scaled 
scores exhibit correlations with each other in the low 
to moderate range and at a lower correlation than 
the internal consistency coefficients reported previ-
ously in this chapter. Corrected correlations between 
adaptive skill area scores and scores of their respec-
tive adaptive domains and the GAC were moderate 
to strong across all samples. The finding that adap-
tive skill area intercorrelations are lower than each 
adaptive skill area’s internal reliability suggests that, 
despite their shared variance, the adaptive skill areas 
measure empirically separable constructs that can be 
interpreted independently of one another. The adap-
tive skill areas also show moderate to strong associa-
tions with the adaptive behavior domains postulated 
by the ABAS-3 theoretical structure.
92 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.2
5.
 In
te
rc
o
rr
el
at
io
n
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
a 
S
ca
le
d
 S
co
re
s 
an
d
 A
d
ap
ti
ve
 D
o
m
ai
n
 a
n
d
 G
A
C
 S
ta
n
d
ar
d
 S
co
re
s:
 
P
ar
en
t/
P
ri
m
ar
y 
C
ar
eg
iv
er
 F
o
rm
 (
A
ge
s 
0
–
5
)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
C
o
m
C
U
FA
H
L
H
S
LS
S
C
S
D
S
o
c
M
O
C
O
N
a
S
O
a
P
R
a
G
A
C
b
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
—
—
—
—
—
—
—
—
—
—
0
.7
5
—
—
0
.6
9
C
o
m
m
u
n
it
y 
U
se
0
.6
0
—
—
—
—
—
—
—
—
—
—
—
0
.7
4
0
.7
8
Fu
n
ct
io
n
al
 P
re
-A
ca
d
em
ic
s
0
.5
3
0
.6
5
—
—
—
—
—
—
—
—
0
.7
5
—
—
0
.7
0
H
o
m
e 
Li
vi
n
g
0
.5
5
0
.6
9
0
.6
0
—
—
—
—
—
—
—
—
—
0
.8
2
0
.8
3
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.5
6
0
.6
4
0
.5
5
0
.6
9
—
—
—
—
—
—
—
—
0
.7
4
0
.7
8
Le
is
u
re
0
.6
1
0
.6
0
0
.5
7
0
.6
7
0
.6
0
—
—
—
—
—
—
0
.8
8
—
0
.8
0
S
el
f-
C
ar
e
0
.4
9
0
.5
5
0
.5
0
0
.6
5
0
.6
3
0
.5
9
—
—
—
—
—
—
0
.7
3
0
.7
4
S
el
f-
D
ir
ec
ti
o
n
0
.6
0
0
.6
3
0
.5
4
0
.7
2
0
.6
6
0
.7
6
0
.6
6
—
—
—
0
.8
0
—
—
0
.8
3
S
o
ci
al
0
.6
2
0
.5
9
0
.5
3
0
.6
6
0
.6
0
0
.7
0
0
.5
9
0
.7
2
—
—
—
0
.8
6
—
0
.7
8
M
o
to
r
0
.4
1
0
.5
1
0
.5
0
0
.5
7
0
.5
9
0
.5
3
0
.5
6
0
.5
6
0
.5
6
—
—
—
—
0
.6
9
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.7
8
0
.7
3
0
.7
9
0
.7
5
0
.6
8
0
.7
3
0
.6
3
0
.8
4
0
.6
8
0
.6
0
—
—
—
0
.8
8
S
o
ci
al
0
.6
2
0
.6
4
0
.5
8
0
.7
4
0
.6
4
0
.9
1
0
.6
3
0
.7
9
0
.8
8
0
.6
5
0
.7
9
—
—
0
.8
4
P
ra
ct
ic
al
0
.6
1
0
.8
2
0
.6
4
0
.8
8
0
.8
4
0
.6
9
0
.8
0
0
.7
6
0
.6
8
0
.6
1
0
.8
2
0
.7
7
—
0
.8
8
G
A
C
0
.7
0
0
.8
0
0
.7
2
0
.8
5
0
.8
0
0
.8
0
0
.7
6
0
.8
4
0
.7
8
0
.7
3
0
.9
2
0
.8
8
0
.9
5
—
M
ea
n
c
10
.5
8
9.
9
5
10
.3
1
10
.2
0
10
.1
9
10
.5
5
10
.3
9
10
.2
1
10
.0
9
10
.7
3
10
0
.8
8
10
0
.0
3
10
0
.6
8
10
0
.3
4
S
D
3.
3
3
3.
17
3.
24
3.
19
3.
0
5
3.
2
5
3.
19
3.
2
1
3.
2
5
2
.9
4
14
.0
2
14
.4
8
13
.7
1
13
.6
6
N
ot
e.
 C
o
m
 =
 C
o
m
m
u
n
ic
at
io
n
; C
U
 =
 C
o
m
m
u
n
it
y 
U
se
; F
A
 =
 F
u
n
ct
io
n
al
 P
re
-A
ca
d
em
ic
s;
 H
L 
=
 H
o
m
e 
Li
vi
n
g;
 H
S
 =
 H
ea
lt
h
 a
n
d
 S
af
et
y;
 L
S
 =
 L
ei
su
re
; S
C
 =
 S
el
f-
C
ar
e;
 S
D
 =
 S
el
f-
D
ir
ec
ti
o
n
; S
o
c 
=
 S
o
ci
al
; 
M
O
 =
 M
o
to
r;
 C
O
N
 =
 C
o
n
ce
p
tu
al
 d
o
m
ai
n
; S
O
 =
 S
o
ci
al
 d
o
m
ai
n
; P
R
 =
 P
ra
ct
ic
al
 d
o
m
ai
n
. n
 =
 1
,0
57
 (
ex
cl
u
d
es
 in
d
iv
id
u
al
s 
u
n
d
er
 1
 y
ea
r 
of
 a
ge
).
a A
d
ap
ti
ve
 d
o
m
ai
n
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
 fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
b
G
A
C
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
(s
) 
fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
c M
ea
n
s 
an
d
 S
D
s 
re
p
o
rt
ed
 u
n
d
er
 c
o
rr
ec
te
d
 a
d
ap
ti
ve
 d
o
m
ai
n
s 
an
d
 G
A
C
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
al
l a
d
ap
ti
ve
 s
ki
ll 
ar
ea
s 
in
cl
u
d
ed
 in
 t
h
e 
co
m
p
os
it
e.
ABAS-3 93Validity
Ta
b
le
 5
.2
6
. I
n
te
rc
o
rr
el
at
io
n
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
a 
S
ca
le
d
 S
co
re
s 
an
d
 A
d
ap
ti
ve
 D
o
m
ai
n
 a
n
d
 G
A
C
 S
ta
n
d
ar
d
 S
co
re
s:
 
P
ar
en
t 
Fo
rm
 (
A
ge
s 
5
–
2
1)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
C
o
m
C
U
FA
H
L
H
S
LS
S
C
S
D
S
o
c
C
O
N
a
S
O
a
P
R
a
G
A
C
b
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
—
—
—
—
—
—
—
—
—
0
.7
6
—
—
0
.7
4
C
o
m
m
u
n
it
y 
U
se
0
.4
8
—
—
—
—
—
—
—
—
—
—
0
.7
7
0
.7
2
Fu
n
ct
io
n
al
 A
ca
d
em
ic
s
0
.6
0
0
.7
3
—
—
—
—
—
—
—
0
.8
4
—
—
0
.8
0
H
o
m
e 
Li
vi
n
g
0
.5
3
0
.6
7
0
.6
8
—
—
—
—
—
—
—
—
0
.8
4
0
.7
9
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.6
1
0
.5
9
0
.6
4
0
.6
5
—
—
—
—
—
—
—
0
.8
2
0
.8
1
Le
is
u
re
0
.6
8
0
.4
8
0
.6
1
0
.5
6
0
.6
6
—
—
—
—
—
0
.9
1
—
0
.7
8
S
el
f-
C
ar
e
0
.5
9
0
.5
2
0
.6
0
0
.6
5
0
.6
9
0
.6
4
—
—
—
—
—
0
.7
9
0
.7
9
S
el
f-
D
ir
ec
ti
o
n
0
.5
5
0
.6
1
0
.6
6
0
.7
2
0
.6
7
0
.6
1
0
.6
8
—
—
0
.8
2
—
—
0
.8
2
S
o
ci
al
0
.7
0
0
.4
5
0
.5
7
0
.5
7
0
.6
5
0
.7
1
0
.6
7
0
.6
9
—
—
0
.8
7
—
0
.7
9
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.8
1
0
.7
0
0
.8
7
0
.7
4
0
.7
4
0
.7
3
0
.7
2
0
.8
6
0
.7
5
—
—
—
0
.9
2
S
o
ci
al
0
.7
2
0
.5
1
0
.6
4
0
.6
1
0
.7
0
0
.9
3
0
.7
0
0
.7
1
0
.9
0
0
.8
1
—
—
0
.8
3
P
ra
ct
ic
al
0
.6
4
0
.8
1
0
.7
7
0.8
7
0
.8
5
0
.6
9
0
.8
2
0
.7
9
0
.6
8
0
.8
6
0
.7
4
—
0
.8
9
G
A
C
0
.7
6
0
.7
5
0
.8
3
0
.8
1
0
.8
3
0
.8
1
0
.8
1
0
.8
4
0
.8
1
0
.9
5
0
.8
8
0
.9
5
—
M
ea
n
c
10
.1
1
10
.2
2
10
.1
8
10
.1
5
10
.3
8
10
.3
0
10
.3
5
10
.2
0
9.
9
8
10
0
.4
8
10
1.
17
10
0
.2
8
10
0
.1
4
S
D
2
.7
6
3.
0
5
3.
0
9
2
.9
4
2
.9
5
3.
0
3
2
.8
1
3.
0
7
2
.8
2
14
.3
3
14
.5
6
14
.1
1
14
.3
1
N
ot
e.
 C
o
m
 =
 C
o
m
m
u
n
ic
at
io
n
; C
U
 =
 C
o
m
m
u
n
it
y 
U
se
; F
A
 =
 F
u
n
ct
io
n
al
 A
ca
d
em
ic
s;
 H
L 
=
 H
o
m
e 
Li
vi
n
g;
 H
S
 =
 H
ea
lt
h
 a
n
d
 S
af
et
y;
 L
S
 =
 L
ei
su
re
; S
C
 =
 S
el
f-
C
ar
e;
 S
D
 =
 S
el
f-
D
ir
ec
ti
o
n
; 
S
o
c 
=
 S
o
ci
al
; C
O
N
 =
 C
o
n
ce
p
tu
al
 d
o
m
ai
n
; S
O
 =
 S
o
ci
al
 d
o
m
ai
n
; P
R
 =
 P
ra
ct
ic
al
 d
o
m
ai
n
. n
 =
 1
,8
71
.
a A
d
ap
ti
ve
 d
o
m
ai
n
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
 fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
b
G
A
C
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
(s
) 
fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
c M
ea
n
s 
an
d
 S
D
s 
re
p
o
rt
ed
 u
n
d
er
 c
o
rr
ec
te
d
 a
d
ap
ti
ve
 d
o
m
ai
n
s 
an
d
 G
A
C
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
al
l a
d
ap
ti
ve
 s
ki
ll 
ar
ea
s 
in
cl
u
d
ed
 in
 t
h
e 
co
m
p
os
it
e.
94 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.2
7.
 In
te
rc
o
rr
el
at
io
n
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
a 
S
ca
le
d
 S
co
re
s 
an
d
 A
d
ap
ti
ve
 D
o
m
ai
n
 a
n
d
 G
A
C
 S
ta
n
d
ar
d
 S
co
re
s:
 
Te
ac
h
er
/D
ay
ca
re
 P
ro
vi
d
er
 F
o
rm
 (
A
ge
s 
2
–
5
)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
C
o
m
FA
S
L
H
S
LS
S
C
S
D
S
o
c
M
O
C
O
N
a
S
O
a
P
R
a
G
A
C
b
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
—
—
—
 —
 —
 —
 —
 —
 —
0
.7
9
 —
 —
0
.7
5
Fu
n
ct
io
n
al
 P
re
-A
ca
d
em
ic
s
0
.6
3
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
3
 —
 —
0
.7
5
S
ch
o
o
l L
iv
in
g
0
.6
0
0
.5
8
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
5
0
.8
1
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.6
4
0
.5
8
0
.7
0
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
3
0
.7
9
Le
is
u
re
0
.7
0
0
.5
9
0
.6
7
0
.6
9
 —
 —
 —
 —
 —
 —
0
.8
9
 —
0
.8
3
S
el
f-
C
ar
e
0
.5
5
0
.5
1
0
.5
9
0
.5
6
0
.6
0
 —
 —
 —
 —
 —
 —
0
.7
7
0
.7
1
S
el
f-
D
ir
ec
ti
o
n
0
.5
8
0
.5
7
0
.7
2
0
.6
5
0
.7
0
0
.5
8
 —
 —
 —
0
.7
9
 —
 —
0
.8
1
S
o
ci
al
0
.6
1
0
.5
3
0
.6
8
0
.6
5
0
.7
4
0
.5
7
0
.7
4
 —
 —
 —
0
.9
0
 —
0
.8
1
M
o
to
r
0
.4
7
0
.6
1
0
.5
5
0
.5
1
0
.5
3
0
.5
7
0
.5
5
0
.5
5
 —
 —
 —
 —
0
.7
0
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.8
3
0
.8
6
0
.7
3
0
.7
1
0
.7
5
0
.6
2
0
.8
3
0
.7
3
0
.6
4
 —
 —
 —
0
.8
6
S
o
ci
al
0
.6
9
0
.6
1
0
.7
1
0
.7
0
0
.9
1
0
.6
1
0
.7
6
0
.9
2
0
.5
8
0
.8
0
 —
 —
0
.8
6
P
ra
ct
ic
al
0
.6
7
0
.6
3
0
.8
8
0
.8
6
0
.7
4
0
.8
1
0
.7
5
0
.7
2
0
.6
1
0
.8
0
0
.7
9
 —
0
.8
7
G
A
C
0
.7
7
0
.7
8
0
.8
2
0
.8
0
0
.8
4
0
.7
3
0
.8
4
0
.8
3
0
.7
4
0
.9
4
0
.9
0
0
.9
2
 —
M
ea
n
c
10
.3
6
10
.4
8
10
.3
3
10
.3
7
10
.2
7
10
.4
2
10
.4
0
10
.2
7
10
.4
8
10
0
.5
4
10
1.
4
4
10
1.
2
1
10
0
.3
9
S
D
2
.4
5
3.
0
1
2
.6
3
2
.4
9
2
.5
3
2
.5
3
2
.8
1
2
.8
1
3.
0
8
13
.9
8
13
.9
4
14
.1
5
14
.0
2
N
ot
e.
 C
o
m
 =
 C
o
m
m
u
n
ic
at
io
n
; F
A
 =
 F
u
n
ct
io
n
al
 P
re
-A
ca
d
em
ic
s;
 S
L 
=
 S
ch
o
o
l L
iv
in
g;
 H
S
 =
 H
ea
lt
h
 a
n
d
 S
af
et
y;
 L
S
 =
 L
ei
su
re
; S
C
 =
 S
el
f-
C
ar
e;
 S
D
 =
 S
el
f-
D
ir
ec
ti
o
n
; S
o
c 
=
 S
o
ci
al
; M
O
 =
 M
o
to
r;
 
C
O
N
 =
 C
o
n
ce
p
tu
al
 d
o
m
ai
n
; S
O
 =
 S
o
ci
al
 d
o
m
ai
n
; P
R
 =
 P
ra
ct
ic
al
 d
o
m
ai
n
. n
 =
 6
57
.
a A
d
ap
ti
ve
 d
o
m
ai
n
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
 fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
b
G
A
C
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
(s
) 
fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
c M
ea
n
s 
an
d
 S
D
s 
re
p
o
rt
ed
 u
n
d
er
 c
o
rr
ec
te
d
 a
d
ap
ti
ve
 d
o
m
ai
n
s 
an
d
 G
A
C
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
al
l a
d
ap
ti
ve
 s
ki
ll 
ar
ea
s 
in
cl
u
d
ed
 in
 t
h
e 
co
m
p
os
it
e.
ABAS-3 95Validity
Ta
b
le
 5
.2
8
. I
n
te
rc
o
rr
el
at
io
n
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
a 
S
ca
le
d
 S
co
re
s 
an
d
 A
d
ap
ti
ve
 D
o
m
ai
n
 a
n
d
 G
A
C
 S
ta
n
d
ar
d
 S
co
re
s:
 
Te
ac
h
er
 F
o
rm
 (
A
ge
s 
5
–
2
1)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
C
o
m
C
U
FA
S
L
H
S
LS
S
C
S
D
S
o
c
C
O
N
a
S
O
a
P
R
a
G
A
C
b
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
5
 —
 —
0
.8
0
C
o
m
m
u
n
it
y 
U
se
0
.6
4
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
0
0
.7
0
Fu
n
ct
io
n
al
 A
ca
d
em
ic
s
0
.6
9
0
.6
8
 —
 —
 —
 —
 —
 —
 —
0
.8
4
 —
 —
0
.7
7
S
ch
o
o
l L
iv
in
g
0
.5
6
0
.5
0
0
.5
4
 —
 —
 —
 —
 —
 —
 —
 —
0
.7
8
0
.8
5
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.6
5
0
.4
8
0
.5
4
0
.6
3
 —
 —
 —
 —
 —
 —
 —
0
.6
7
0
.7
4
Le
is
u
re
0
.5
0
0
.4
5
0
.5
1
0
.6
3
0
.6
0
 —
 —
 —
 —
 —
0
.8
9
 —
0
.7
8
S
el
f-
C
ar
e
0
.6
8
0
.5
3
0
.6
4
0
.6
4
0
.6
8
0
.6
1
 —
 —
 —
 —
 —
0
.7
1
0
.7
1
S
el
f-
D
ir
ec
ti
o
n
0
.6
9
0
.5
6
0
.6
3
0
.6
7
0
.7
1
0
.6
2
0
.7
9
 —
 —
0
.8
3
 —
 —
0
.8
4
S
o
ci
al
0
.6
4
0
.4
6
0
.5
6
0
.6
7
0
.7
3
0
.6
5
0
.7
5
0
.7
3
 —
 —
0
.8
8
 —
0
.8
0
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.8
7
0
.7
0
0
.8
6
0
.7
8
0
.6
1
0
.6
8
0
.5
9
0
.8
5
0
.7
0
 —
 —
 —
0
.8
6
S
o
ci
al
0
.6
8
0
.5
2
0
.5
9
0
.7
6
0
.6
5
0
.9
1
0
.6
4
0
.7
5
0
.8
9
0
.7
6
 —
 —
0
.8
3
P
ra
ct
ic
al
0
.7
2
0
.8
0
0
.7
2
0
.8
5
0
.7
8
0
.7
1
0
.7
7
0
.7
6
0
.7
2
0
.8
4
0
.7
8
 —
0
.9
0
G
A
C
0
.8
1
0
.7
5
0
.7
9
0
.8
6
0
.7
3
0
.7
9
0
.7
2
0
.8
4
0
.8
0
0
.9
4
0
.8
8
0
.9
5
 —
M
ea
n
c
10
.2
3
10
.7
1
10
.2
9
10
.1
1
10
.0
1
10
.0
8
10
.2
6
10
.1
1
9.
9
2
10
0
.7
2
10
1.
2
6
10
1.
10
10
0
.7
3
S
D
2
.7
4
3.
12
2
.8
7
2
.7
6
2
.5
6
2
.7
1
2
.6
3
2
.7
3
2
.6
5
14
.4
8
13
.9
9
14
.2
0
14
.3
2
N
ot
e.
 C
o
m
 =
 C
o
m
m
u
n
ic
at
io
n
; C
U
 =
 C
o
m
m
u
n
it
y 
U
se
; F
A
 =
 F
u
n
ct
io
n
al
 A
ca
d
em
ic
s;
 S
L 
=
 S
ch
o
o
l L
iv
in
g;
 H
S
 =
 H
ea
lt
h
 a
n
d
 S
af
et
y;
 L
S
 =
 L
ei
su
re
; S
C
 =
 S
el
f-
C
ar
e;
 S
D
 =
 S
el
f-
D
ir
ec
ti
o
n
; 
S
o
c 
=
 S
o
ci
al
; C
O
N
 =
 C
o
n
ce
p
tu
al
 d
o
m
ai
n
; S
O
 =
 S
o
ci
al
 d
o
m
ai
n
; P
R
 =
 P
ra
ct
ic
al
 d
o
m
ai
n
. n
 =
 1
,8
2
3.
a A
d
ap
ti
ve
 d
o
m
ai
n
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
 fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
b
G
A
C
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
(s
) 
fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
c M
ea
n
s 
an
d
 S
D
s 
re
p
o
rt
ed
 u
n
d
er
 c
o
rr
ec
te
d
 a
dap
ti
ve
 d
o
m
ai
n
s 
an
d
 G
A
C
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
al
l a
d
ap
ti
ve
 s
ki
ll 
ar
ea
s 
in
cl
u
d
ed
 in
 t
h
e 
co
m
p
os
it
e.
96 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.2
9
. I
n
te
rc
o
rr
el
at
io
n
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
a 
S
ca
le
d
 S
co
re
s 
an
d
 A
d
ap
ti
ve
 D
o
m
ai
n
 a
n
d
 G
A
C
 S
ta
n
d
ar
d
 S
co
re
s:
 
A
d
u
lt
 F
o
rm
 (
S
el
f-
R
ep
o
rt
) 
(A
ge
s 
16
–
8
9
)
A
d
ap
ti
ve
 s
ki
ll 
 
ar
ea
/C
o
m
p
o
si
te
C
o
m
C
U
FA
H
L
H
S
LS
S
C
S
D
S
o
c
W
K
C
O
N
a
S
O
a
P
R
-4
a
P
R
-5
a
G
A
C
-9
b
G
A
C
-1
0
b
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
1
 —
 —
 —
0
.7
4
0
.7
2
C
o
m
m
u
n
it
y 
U
se
0
.7
3
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
0
0
.7
6
0
.8
3
0
.8
1
Fu
n
ct
io
n
al
 
A
ca
d
em
ic
s
0
.6
5
0
.7
7
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
6
 —
 —
 —
0
.8
3
0
.8
3
H
o
m
e 
Li
vi
n
g
0
.5
9
0
.6
8
0
.6
8
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
4
0
.7
8
0
.8
1
0
.7
9
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.5
8
0
.6
5
0
.6
9
0
.7
1
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
4
0
.8
1
0
.8
2
0
.8
2
Le
is
u
re
0
.5
9
0
.7
0
0
.6
8
0
.6
6
0
.6
7
 —
 —
 —
 —
 —
 —
0
.8
9
 —
 —
0
.8
2
0
.8
0
S
el
f-
C
ar
e
0
.5
3
0
.5
8
0
.6
1
0
.6
3
0
.7
0
0
.6
3
 —
 —
 —
 —
 —
 —
0
.7
9
0
.7
5
0
.7
6
0
.7
5
S
el
f-
D
ir
ec
ti
o
n
0
.5
9
0
.6
5
0
.6
9
0
.6
8
0
.7
1
0
.6
9
0
.6
6
 —
 —
 —
0
.8
2
 —
 —
 —
0
.8
2
0
.8
2
S
o
ci
al
0
.5
9
0
.6
3
0
.6
6
0
.6
3
0
.6
7
0
.7
1
0
.6
4
0
.7
4
 —
 —
 —
0
.8
9
 —
 —
0
.8
0
0
.8
0
W
o
rk
0
.2
5
0
.3
8
0
.4
3
0
.3
5
0
.4
3
0
.3
5
0
.3
5
0
.4
0
0
.4
0
 —
 —
 —
 —
0
.5
9
 —
0
.5
1
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.8
5
0
.8
2
0
.8
8
0
.7
3
0
.7
3
0
.7
5
0
.6
6
0
.8
5
0
.7
5
0
.4
2
 —
 —
 —
 —
0
.9
0
0
.8
9
S
o
ci
al
0
.6
4
0
.7
2
0
.7
2
0
.6
9
0
.7
1
0
.9
2
0
.6
7
0
.7
7
0
.9
2
0
.4
0
0
.8
1
 —
 —
 —
0
.8
6
0
.8
6
P
ra
ct
ic
al
-4
0
.6
9
0
.8
3
0
.7
9
0
.8
7
0
.8
6
0
.7
7
0
.8
2
0
.7
6
0
.7
3
0
.4
4
0
.8
6
0
.8
1
 —
0
.9
4
0
.9
1
 —
P
ra
ct
ic
al
-5
0
.6
5
0
.8
0
0
.7
8
0
.8
1
0
.8
3
0
.7
3
0
.7
8
0
.7
5
0
.7
3
0
.6
9
0
.8
3
0
.7
9
0
.9
5
 —
 —
0
.9
0
G
A
C
-9
0
.7
7
0
.8
4
0
.8
4
0
.8
3
0
.8
3
0
.8
4
0
.7
8
0
.8
3
0
.8
2
0
.4
6
0
.9
4
0
.9
0
0
.9
6
0
.9
3
 —
 —
G
A
C
-1
0
0
.7
4
0
.8
3
0
.8
4
0
.8
1
0
.8
2
0
.8
2
0
.7
6
0
.8
3
0
.8
1
0
.6
0
0
.9
3
0
.8
8
0
.9
5
0
.9
7
0
.9
8
 —
M
ea
n
c
10
.3
8
10
.2
3
10
.3
8
10
.6
3
10
.9
7
10
.1
7
10
.6
0
10
.3
8
10
.4
6
9.
2
9
10
0
.3
3
9
9.
9
1
9
9.
8
3
9
9.
9
5
10
0
.4
9
10
0
.1
4
S
D
2
.8
7
2
.8
0
2
.8
2
3.
2
0
3.
3
1
2
.7
1
3.
0
8
2
.8
1
2
.8
4
4
.4
2
13
.6
4
13
.1
2
13
.4
4
13
.7
8
14
.3
0
14
.2
9
N
ot
e.
 C
o
m
 =
 C
o
m
m
u
n
ic
at
io
n
; C
U
 =
 C
o
m
m
u
n
it
y 
U
se
; F
A
 =
 F
u
n
ct
io
n
al
 A
ca
d
em
ic
s;
 H
L 
=
 H
o
m
e 
Li
vi
n
g;
 H
S
 =
 H
ea
lt
h
 a
n
d
 S
af
et
y;
 L
S
 =
 L
ei
su
re
; S
C
 =
 S
el
f-
C
ar
e;
 S
D
 =
 S
el
f-
D
ir
ec
ti
o
n
; S
o
c 
=
 S
o
ci
al
; W
K
 =
 W
o
rk
; 
C
O
N
 =
 C
on
ce
p
tu
al
 d
om
ai
n
; S
O
 =
 S
oc
ia
l d
om
ai
n
; P
R
-4
 =
 P
ra
ct
ic
al
 d
om
ai
n
 w
it
h
ou
t W
or
k;
 P
R
-5
 =
 P
ra
ct
ic
al
 d
om
ai
n
 w
it
h
 W
or
k;
 G
A
C
-9
 =
 G
A
C
 w
it
h
ou
t W
or
k;
 G
A
C
-1
0
 =
 G
A
C
 w
it
h
 W
or
k.
 n
 =
 1
,0
14
; n
 w
it
h
 W
or
k 
=
 9
9
4
.
a A
d
ap
ti
ve
 d
o
m
ai
n
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
 fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
b
G
A
C
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
(s
) 
fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
c M
ea
n
s 
an
d
 S
D
s 
re
p
o
rt
ed
 u
n
d
er
 c
o
rr
ec
te
d
 a
d
ap
ti
ve
 d
o
m
ai
n
s 
an
d
 G
A
C
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
al
l a
d
ap
ti
ve
 s
ki
ll 
ar
ea
s 
in
cl
u
d
ed
 in
 t
h
e 
co
m
p
os
it
e.
ABAS-3 97Validity
Ta
b
le
 5
.3
0
. I
n
te
rc
o
rr
el
at
io
n
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
a 
S
ca
le
d
 S
co
re
s 
an
d
 A
d
ap
ti
ve
 D
o
m
ai
n
 a
n
d
 G
A
C
 S
ta
n
d
ar
d
 S
co
re
s:
 
A
d
u
lt
 F
o
rm
 (
R
at
ed
 b
y 
O
th
er
s)
 (
A
ge
s 
16
–
8
9
)
A
d
ap
ti
ve
 s
ki
ll 
 
ar
ea
/C
o
m
p
o
si
te
C
o
m
C
U
FA
H
L
H
S
LS
S
C
S
D
S
o
c
W
K
C
O
N
a
S
O
a
P
R
-4
a
P
R
-5
a
G
A
C
-9
b
G
A
C
-1
0
b
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
0
 —
 —
 —
0
.8
0
0
.7
8
C
o
m
m
u
n
it
y 
U
se
0
.6
9
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.7
7
0
.7
3
0
.7
8
0
.7
4
Fu
n
ct
io
n
al
 
A
ca
d
em
ic
s
0
.5
9
0
.6
9
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
2
 —
 —
 —
0
.7
7
0
.7
5
H
o
m
e 
Li
vi
n
g
0
.5
6
0
.6
4
0
.6
6
 —
 —
 —
 —
 —
 —
 —
 —
 —
0
.7
9
0
.7
2
0
.7
3
0
.7
0
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.5
6
0
.6
2
0
.6
5
0
.6
1
 —
 —
 —
 —
 —
 —
 —
 —
0
.8
0
0
.7
6
0
.7
3
0
.7
0
Le
is
u
re
0
.6
0
0
.6
7
0
.6
4
0
.6
2
0
.5
7
 —
 —
 —
 —
 —
 —
0
.8
9
 —
 —
0
.8
0
0
.7
9
S
el
f-
C
ar
e
0
.5
4
0
.5
6
0
.5
6
0
.6
1
0
.6
3
0
.6
1
 —
 —
 —
 —
 —
 —
0
.7
8
0
.7
1
0
.7
9
0
.7
6
S
el
f-
D
ir
ec
ti
o
n
0
.6
2
0
.6
4
0
.6
6
0
.6
8
0
.6
5
0
.6
7
0
.5
8
 —
 —
 —
0
.8
2
 —
 —
 —
0
.8
1
0
.7
8
S
o
ci
al
0
.5
9
0
.6
3
0
.6
5
0
.6
2
0
.6
2
0
.7
1
0
.6
1
0
.7
4
 —
 —
 —
0
.8
9
 —
 —
0
.8
0
0
.7
7
W
o
rk
0
.2
8
0
.3
9
0
.4
2
0
.2
9
0
.3
9
0
.3
3
0
.3
2
0
.3
7
0
.3
4
 —
 —
 —
 —
0
.5
8
 —
0
.4
8
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.8
3
0
.7
5
0
.8
5
0
.7
1
0
.6
9
0
.7
2
0
.6
3
0
.8
5
0
.7
4
0
.3
9
 —
 —
 —
 —
0
.8
9
0
.8
7
S
o
ci
al
0
.6
1
0
.6
7
0
.6
7
0
.6
4
0
.6
1
0
.9
1
0
.6
3
0
.7
3
0
.9
1
0
.3
3
0
.7
8
 —
 —
 —
0
.8
3
0
.8
1
P
ra
ct
ic
al
-4
0
.6
6
0
.8
0
0
.7
3
0
.8
2
0
.8
3
0
.7
1
0
.8
2
0
.7
2
0
.7
1
0
.3
9
0
.8
3
0
.7
6
 —
0
.9
3
0
.8
9
 —
P
ra
ct
ic
al
-5
0
.6
1
0
.7
7
0
.7
3
0
.7
5
0
.7
9
0
.6
8
0
.7
5
0
.6
7
0
.6
7
0
.6
8
0
.7
9
0
.7
2
0
.9
3
 —
 —
0
.8
7
G
A
C
-9
0
.7
5
0
.8
0
0
.8
1
0
.7
9
0
.7
9
0
.8
0
0
.7
6
0
.8
2
0
.8
1
0
.4
0
0
.9
4
0
.8
8
0
.9
5
0
.9
0
 —
 —
G
A
C
-1
0
0
.7
3
0
.8
0
0
.8
0
0
.7
6
0
.7
8
0
.7
8
0
.7
3
0
.7
9
0
.7
9
0
.5
8
0
.9
1
0
.8
5
0
.9
3
0
.9
6
0
.9
7
 —
M
ea
n
c
11
.0
9
10
.5
3
10
.7
1
10
.4
3
11
.0
5
10
.2
6
10
.8
1
10
.5
9
10
.4
4
9.
4
3
10
0
.0
3
10
0
.2
6
9
9.
3
1
9
7.
76
9
9.
4
1
9
8
.8
5
S
D
3.
3
1
3.
0
9
3.
15
3.
0
5
3.
4
0
2
.7
9
3.
37
3.
0
7
2
.8
6
4
.8
6
13
.9
2
13
.3
7
13
.3
5
13
.6
7
13
.5
1
13
.5
4
N
ot
e.
 C
o
m
 =
 C
o
m
m
u
n
ic
at
io
n
; C
U
 =
 C
o
m
m
u
n
it
y 
U
se
; F
A
 =
 F
u
n
ct
io
n
al
 A
ca
d
em
ic
s;
 H
L 
=
 H
o
m
e 
Li
vi
n
g;
 H
S
 =
 H
ea
lt
h
 a
n
d
 S
af
et
y;
 L
S
 =
 L
ei
su
re
; S
C
 =
 S
el
f-
C
ar
e;
 S
D
 =
 S
el
f-
D
ir
ec
ti
o
n
; S
o
c 
=
 S
o
ci
al
; W
K
 =
 W
o
rk
; 
C
O
N
 =
 C
on
ce
p
tu
al
 d
om
ai
n
; S
O
 =
 S
oc
ia
l d
om
ai
n
; P
R
-4
 =
 P
ra
ct
ic
al
 d
om
ai
n
 w
it
h
ou
t W
or
k;
 P
R
-5
 =
 P
ra
ct
ic
al
 d
om
ai
n
 w
it
h
 W
or
k;
 G
A
C
-9
 =
 G
A
C
 w
it
h
ou
t W
or
k;
 G
A
C
-1
0
 =
 GA
C
 w
it
h
 W
or
k.
 n
 =
 1
,0
0
1;
 n
 w
it
h
 W
or
k 
=
 9
3
0
.
a A
d
ap
ti
ve
 d
o
m
ai
n
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
 fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
b
G
A
C
 c
o
rr
el
at
io
n
s 
w
er
e 
co
rr
ec
te
d
 b
y 
re
m
ov
in
g 
th
e 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
 s
ca
le
d
 s
co
re
(s
) 
fr
o
m
 t
h
e 
st
an
d
ar
d
 s
co
re
s.
c M
ea
n
s 
an
d
 S
D
s 
re
p
o
rt
ed
 u
n
d
er
 c
o
rr
ec
te
d
 a
d
ap
ti
ve
 d
o
m
ai
n
s 
an
d
 G
A
C
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
al
l a
d
ap
ti
ve
 s
ki
ll 
ar
ea
s 
in
cl
u
d
ed
 in
 t
h
e 
co
m
p
os
it
e.
98 ABAS-3 Chapter 5 Reliability and Validity
Factor Structure 
Evidence relating to factor structure is integral to 
examining a test’s validity. The theoretical founda-
tions of the ABAS-3 assert that the 10 adaptive skill 
areas constitute important aspects of adaptive behav-
ior. Although the adaptive skill areas are assumed to 
be somewhat independent of one another, AAMR’s 
(2002) criteria and the current descriptions in AAIDD 
(2010) suggest that these adaptive skill areas may be 
grouped into three domains of adaptive behavior, 
namely Conceptual, Social, and Practical (AAMR, 
2002). Based on this conceptual background, confir-
matory factor analysis was applied to test both one- 
and three-factor models, and to compare these models 
to one with no common factors (null model). The data 
were analyzed using Mplus (Version 7) software.
The factor structure of the ABAS-3 was examined 
within the standardization samples described earlier 
in the manual (corresponding to forms): Parent/
Primary Caregiver, Teacher/Daycare Provider, Parent, 
Teacher, and Adult (self-report and rated by others). 
In the hypothesized three-factor model, adaptive 
skill areas were combined to create three factors that 
replicate the structure of the Conceptual, Social, and 
Practical adaptive domain scores. For the one-factor 
model, all available adaptive skill areas for each form 
were combined into a single factor (analogous to the 
GAC score). For both models, the Work and Motor 
adaptive skill areas were excluded. This was done 
because of missing data (in the case of Work, which 
is rated only for those of certain ages who have jobs) 
and because, according to the AAMR (2002) guide-
lines, the ABAS-3 does not include the Motor adaptive 
skill area in any of the three adaptive domain scores.
For each standardization sample, Table 5.31 presents 
model fit statistics for both a one- and three-factor 
model compared with the null model. Both the one- 
and three-factor model show improved fit over the 
null model. Overall, a conservative one-factor model 
provides a good fit to the observed data from the 
standardization samples. These findings are consis-
tent with the research summarized by AAIDD (2010) 
that most adaptive functioning instruments measure 
a general, global factor. The results also indicate that 
the three-factor model produces a close fit to the 
data, which supports the categorization of adaptive 
skill areas into three more general adaptive domains 
(AAMR, 2002; AAIDD, 2010). These results suggest 
that the ABAS-3 functions as both a comprehensive 
measure of adaptive behavior as well as one that 
can distinguish meaningfully among different focal 
domains of adaptive skill.
Correlations With Other Variables
A test’s validity is traditionally evaluated, in part, by 
evidence that examines relationships between the 
test and other variables. The ABAS-3 research base 
includes new studies of concurrent validity, which 
refers to relationships with other measures obtained 
approximately at the same time. The other measures 
described in this section include the previous edi-
tion of the ABAS (ABAS-II), the Vineland Adaptive 
Behavior Scales, the Behavior Assessment System for 
Children, Second Edition (BASC-2), and the Reynolds 
Intellectual Assessment Scales™ (RIAS™). Several of 
these studies (e.g., ABAS-II, Vineland-II) fall under the 
category of convergent validity, which refers to the 
degree of association between the ABAS-3 and other 
measures of the same or similar constructs.
Equivalence Between the ABAS-3 and ABAS-II
A series of analyses examined the level of equiva-
lence between ABAS second-edition and third-edition 
scores. Participants rated the same individuals on 
the ABAS-II and ABAS-3 forms in the same testing 
session. The order of administration was counter-
balanced across each data collection site so that 
half received the ABAS-II first and half received 
the ABAS-3 first. Separate studies were conducted 
for each of the forms. The results are presented in 
Tables 5.32 through 5.37.
The rated individuals in these studies included chil-
dren, adolescents, and adults spanning the intended 
age range of each form. Demographically, the sam-
ples were similar: approximately evenly split between 
males and females; about 80% White and 20% ethnic 
minority; and relatively high SES (about 80% with 
a household education level of bachelor’s degree or 
higher).
Two analyses were conducted on the equivalence 
data: the effect size of the difference between the 
ABAS-II and ABAS-3 adaptive skill area scaled scores, 
adaptive domain standard scores, and GAC scores; 
and corrected Pearson correlation coefficients. These 
analyses were expected to show a moderate degree 
of equivalence between the scores of the ABAS-II and 
the ABAS-3. Specifically, effect sizes were expected to 
be small (absolute value of .3 to .4 or less), and cor-
rected correlation coefficients were expected to be in 
the range of .60 to .80.
ABAS-3 99Validity
The equivalence results in Tables 5.32 through 5.37 
are affected by several factors. Stronger equivalence 
is driven by the high degree of similarity in item 
content between the two editions of the ABAS. At 
the same time, weaker equivalence is driven by item 
changes between the two editions, and by the fact that 
scaled and standard scores are based on two different 
standardization samples collected at least 15 years 
apart, by different organizations under different 
conditions. For the most part, these countervailing 
factors produced the expected moderate degree of 
equivalence between the two editions of the ABAS.
On the Parent/Primary Caregiver Form, the average 
effect size across all scores was −.15, and the aver-
age corrected correlation was .75. For GAC, the effect 
size was −.13, and the corrected correlation was .88. 
On the Parent Form, the average effect size across all 
scores was −.20, and the average corrected correlation 
was .72. For GAC, the effect size was −.20, and the cor-
rected correlation was .88. 
On the Teacher/Daycare Provider Form, the average 
effect size across all scores was .13, and the average 
corrected correlation was .89. For GAC, the effect size 
was .23, and the corrected correlation was .93. On the 
Teacher Form, the average effect size across all scores 
was −.10, and the average corrected correlation was 
.81. For GAC, the effect size was .16, and the corrected 
correlation was .89.
On the Adult Form (self-report) the average effect size 
across all scores was .21, and the average corrected 
correlation was .79. For GAC, the effect size was .24, 
and the corrected correlation was .90. On the Adult 
Form (rated by others), the average effect size across 
all scores was .16, and the average corrected correla-
tion was .79. For GAC, the effect size was .33, and the 
corrected correlation was .90.
One anomaly in these tables deserves further com-
ment. On the Parent/Primary Caregiver Form, the 
mean scaled score for the Self-Care adaptive skill area 
was 3.23 points higher on the ABAS-3 than on the 
ABAS-II, resulting in an effect size of −1.22, far greater 
in absolute value than any other observed across the 
studies. The sample size in the Parent/PrimaryCare-
giver Form equivalency study was 167, which is large 
enough to support a robust finding.
Because the Self-Care scale includes 24 items on both 
editions of the ABAS, raw scores are directly compara-
ble between the two editions. The mean raw score dif-
ference was −2.4, and thus in the opposite direction of 
the scaled score difference. Overall, therefore, when 
compared to the ABAS-II, lower Self-Care raw scores 
on the ABAS-3 are yielding higher scaled scores.
Could this focal change between the two editions be 
due to revisions in item content? Of the 24 items on 
the ABAS-3 Self-Care scale, 17 are identical to the 
ABAS-II, 3 were revised for the new edition, and 4 
are entirely new. This degree of item change between 
the two editions is similar to that instituted on the 
other scales, across all forms, none of which showed 
the same large score difference between ABAS-II and 
ABAS-3.
A more likely explanation has to do with a real change 
in the normative standard for evaluating the adap-
tive behavior of young children. Such a change is not 
surprising, given the 15-year gap between collection 
of the ABAS-II and ABAS-3 standardization samples, 
and cultural changes that have occurred during that 
time span. Essentially, the finding suggests that at the 
time of ABAS-II standardization, parents generally 
saw their youngest children as more independent 
and more able to care for themselves than did parents 
during the much more recent period of ABAS-3 
standardization. To put it another way, Self-Care raw 
scores for the ABAS-II standardization sample were 
higher overall than in the ABAS-3 standardization 
sample. Therefore, an individual child’s raw score 
would result in a standard score that is lower in the 
ABAS-II standardization sample than in the ABAS-3 
standardization sample. Thus, when present-day par-
ents describe the self-care skills of their children (via 
providing a set of ABAS ratings), and those ratings are 
scored against the ABAS-II norms, the result is lower-
than-expected scaled scores.
100 ABAS-3 Chapter 5 Reliability and Validity
Table 5.31. Goodness-of-Fit Statistics for Confirmatory Factor Analysis
Goodness-of-fit indices of the one- and three-factor models
Standardization sample n x2 df p SRMR RMSEA CFI TLI
Parent/Primary Caregiver 1,057
Null model 4,630.46 360.82
Self-Care 10.9 1.7 11.4 2.1 –0.27 0.50 0.64
Self-Direction 11.6 2.4 10.9 2.4 0.28 0.68 0.76
Social 11.2 2.5 10.9 2.3 0.16 0.94 0.96
Work 12.1 1.7 11.4 3.1 0.29 0.80 0.79
Adaptive domain
Conceptual 109.2 12.3 104.4 12.2 0.39 0.85 0.89
Social 106.2 15.2 101.4 12.4 0.35 0.89 0.92
Practical 109.1 13.2 105.3 12.2 0.30 0.83 0.88
GAC 108.1 12.7 105.0 13.0 0.24 0.87 0.90
Note. n = 37.
Table 5.37. Correlations Between ABAS-II and ABAS-3 Scaled and Standard Scores: 
Adult Form, Rated by Others (Ages 16–89)
ABAS-II ABAS-3
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d r Corrected r
Adaptive skill area
Communication 11.5 2.2 11.8 3.0 –0.13 0.75 0.75
Community Use 11.3 2.7 11.0 3.0 0.10 0.73 0.73
Functional Academics 11.5 2.3 11.5 2.9 –0.01 0.70 0.71
Home Living 11.7 2.3 10.4 2.9 0.50 0.88 0.89
Health and Safety 11.1 2.3 11.2 3.5 –0.03 0.72 0.65
Leisure 11.1 2.8 10.0 3.0 0.38 0.84 0.84
Self-Care 10.7 2.3 11.7 2.8 –0.40 0.61 0.63
Self-Direction 11.2 2.8 10.6 3.2 0.19 0.88 0.87
Social 11.6 2.5 11.0 2.3 0.23 0.69 0.78
Work 11.3 2.2 11.3 4.2 0.01 0.77 0.65
Adaptive domain
Conceptual 106.8 13.0 102.8 13.8 0.30 0.90 0.91
Social 106.6 13.6 101.6 13.9 0.36 0.83 0.85
Practical 107.5 14.4 101.1 14.0 0.45 0.88 0.89
GAC 106.7 12.7 102.4 14.0 0.33 0.88 0.90
Note. n = 37.
104 ABAS-3 Chapter 5 Reliability and Validity
Correlations With the Vineland Adaptive Behavior 
Rating Scale, Second Edition
The ABAS-II manual presented a set of studies docu-
menting the relationship between the ABAS-II scales 
and those of the Vineland Adaptive Behavior Scale, 
Classroom and Interview Editions. Since that time, 
the second edition of the Vineland (Vineland-II) has 
been published. The ABAS-3 clinical validity research 
includes new studies with the Vineland-II Parent/
Caregiver Rating Form and Teacher Rating Form, 
covering the preschool and school-age forms of the 
ABAS-3. Participants were administered ABAS-3 and 
Vineland-II in the same testing session, with the order 
of administration counterbalanced across each data 
collection site so that half received that ABAS-3 first 
and half received the Vineland-II first. All samples 
included data from children and adolescents with 
clinical disorders, as well as data from typically devel-
oping individuals in the standardization sample. 
The results of the analyses are shown in Tables 5.38 
to 5.41. Each table presents correlations between the 
scores of the ABAS-3 and those of the Vineland-II, 
along with descriptive statistics for all scores.
A study with the ABAS-3 Parent/Primary Caregiver 
Form is summarized in Table 5.38. The sample 
consisted of 92 children ranging in age from 1 to 
71 months, with a mean age of 39.2 months (SD = 20.1). 
Forty-one of the children were typically developing, 
and the remainder were drawn from the clinical 
samples (30 autism spectrum disorder, 20 intellectual 
disability, 1 attention-deficit/hyperactivity disorder). 
Sixty of the children (63.8%) were boys. The sample 
was 77.7% White, 5.4% Black, 6.4% Hispanic, and 
10.5% other ethnicities. In terms of SES, 46.8% of the 
heads of household had a 4-year college degree or 
higher, and 12.8% had a high-school degree or less.
In this sample, mean ABAS-3 GAC was 79.2 (SD = 22.5), 
and the mean adaptive skill area scaled scores ranged 
from 6.5 (Social) to 8.6 (Motor). Mean Vineland-II 
Adaptive Behavior Composite Score was 81.5 
(SD = 22.2). Corrected correlations between the scores 
of the two measures ranged from moderate to 
strong, averaging .66 over the entire table. ABAS-3 
GAC correlated with Vineland-II Adaptive Behavior 
Composite at .77.
A study with the ABAS-3 Parent Form is summarized 
in Table 5.39. The sample consisted of 28 children 
and adolescents ranging in age from 5 to 20 years, 
with a mean age of 10.3 years (SD = 4.7). The sample 
included 15 typically developing students, 5 students 
with ASD, 3 with ID, and 5 with ADHD. Fifteen of the 
students (53.6%) were boys. The sample was 67.9% 
White, 7.1% Black, 7.1% Hispanic, and 17.9% other 
ethnicities. The sample was primarily high SES, with 
64.3% of the heads of household having a 4-year col-
lege degree or higher, and 21.4% a high-school degree 
or less.
Reflecting the mixed composition of the sample, 
most adaptive behavior scores were in the aver-
age range, but many were at least two-thirds of a 
standard deviation below the mean. Mean ABAS-3 
GAC was 90.6 (SD = 19.4), and the mean adaptive 
skill area scaled scores ranged from 7.8 (Self-Direc-
tion) to 9.0 (Community Use and Self-Care). Mean 
Vineland-II Adaptive Behavior Composite Score was 
86.0 (SD = 27.0). Corrected correlations between the 
scores of the two measures ranged from moderate to 
strong, averaging .67 over the entire table. ABAS-3 
and Vineland-II scores reflecting similar item con-
tent were strongly correlated with each other. The 
two communication scores correlated at .79, the two 
social composites correlated at .90, and ABAS-3 GAC 
correlated with Vineland-II Adaptive Behavior Com-
posite at .80 (the Vineland-II Motor Skills Domain was 
excluded from the analysis because of missing data).
Table 5.40 documents the relationship between Vine-
land-II Teacher Rating Form scores and those of the 
ABAS-3 Teacher/Daycare Provider Form. This sample 
consisted of 55 children ranging in age from 35 to 
71 months, with a mean age of 54.1 months (SD = 9.6). 
The sample included 37 children with ASD, 11 with 
ID, 1 with ADHD, and 6 typically developing chil-
dren. Thirty-seven of the children (67.3%) were boys. 
The sample was 70.9% White, 10.9% Black, 10.9% 
Hispanic, and 7.3% other ethnicities. Socioeconomic 
status was indexed by head-of-household education 
level. The sample tended toward higher SES, with 
38.2% of the heads of household having a 4-year col-
lege degree or higher, and 18.2% a high-school degree 
or less.
ABAS-3 105Validity
As would be expected with a predominantly clinical 
sample, adaptive behavior scores fell in the low to 
extremely low ranges. Mean ABAS-3 GAC was 66.3 
(SD = 17.5), and the mean adaptive skill area scaled 
scores ranged from 3.9 (Social) to 5.6 (Self-Care). 
Mean Vineland-II Adaptive Behavior Composite 
Score was 67.2 (SD = 19.8). Corrected correlations 
between the scores of the two measures were mostly 
in the strong (.7 to .9) range, averaging .75 over the 
entire table. ABAS-3 and Vineland-II scores reflecting 
similar item content were strongly correlated with 
each other. For example, the two communication 
scores correlated at .77, the two social composites cor-
related at .85, the two motor scores correlated at .79, 
and ABAS-3 GAC correlated with Vineland-II Adap-
tive Behavior Composite at .86.
Table 5.41 details a study with the ABAS-3 Teacher 
Form. The table presents the analysis of data from 
34 children and adolescents ranging in age from 5 
to 20 years, with a mean age of 12.2 years (SD = 5.1). 
The sample consisted mostly of typically developing 
students (23), but also included 7 students with ASD, 
1 with ID, and 3 with ADHD. Fifteen of the students 
(44.1%) were boys. The sample was 64.7% White, 
20.6% Black, 11.8% Hispanic, and 2.9% other ethnici-
ties. The sample was primarily high SES, with 64.7% 
of the heads of household having a 4-year college 
degree or higher, and 11.8% had a high-school 
degree or less.
Because of the higher proportion of typically 
developing students in the Teacher Form sample, 
all adaptive behavior scores were in the average 
range. Mean ABAS-3 GAC was 99.4 (SD = 21.2), and 
the mean adaptive skill area scaled scores ranged 
from 9.0 (Social) to 10.5 (Community Use). Mean 
Vineland-II Adaptive Behavior Composite Score was 
98.2 (SD = 28.4). Corrected correlations between the 
scores of the two measures were mostly in the strong 
(.7 to .9) range, averaging .77 over the entire table. 
ABAS-3 and Vineland-II scores reflecting similar item 
content were strongly correlated with each other. The 
two communication scoresand functional communication. Across all cor-
relations between ABAS-3 scores and BASC-2 scores 
representing positive behaviors, the average value of 
r was .48.
On the teacher forms, ABAS-3 scores fell in the low to 
extremely low ranges. Mean ABAS-3 GAC was 71.6 
(SD = 15.4), and the mean adaptive skill area scaled 
scores ranged from 4.6 (Communication) to 6.0 
(Self-Care). The BASC-2 data were scored against the 
clinical norms, resulting in mean T scores of 48.9 
(SD = 8.4) for the Externalizing Problems Compos-
ite, 46.4 (SD = 11.0) for the Internalizing Problems 
Composite, and 41.4 (SD = 8.7) for the Adaptive Skills 
Composite.
As with the ABAS-3 parent forms, the teacher scores 
showed an expected pattern of correlations, with 
mostly negative correlations with BASC-2 scores 
representing problematic behavior and symptoms, 
and mostly positive correlations with BASC-2 scores 
representing positive behavior. In general, the corre-
lations were smaller in magnitude than on the parent 
forms. The ABAS-3 teacher-rated GAC correlated 
at .38 with the BASC-2 Adaptive Skills Composite. 
Across all correlations between ABAS-3 scores and 
BASC-2 scores representing positive behaviors, the 
average value of r was .35.
The BASC-2 studies add to the Vineland-II studies 
by showing an expected pattern of correlations with 
another measure that has adaptive behavior scales. 
In addition, the BASC-2 studies provide evidence 
of divergent validity by illustrating that the ABAS-3 
scores correlate negatively with scores that rep-
resent conceptual opposites of adaptive behavior 
(e.g., aggression, depression, withdrawal).
ABAS-3 111Validity
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2
.1
4
1.
8
4
1.
8
4
8
.9
4
7.
1
5
3.
1
4
1.
6
S
D
9.
5
8
.7
14
.5
8
.7
8
.7
11
.2
9.
7
7.
8
8
.3
10
.6
10
.4
10
.5
8
.5
11
.7
8
.7
9.
0
N
ot
e.
 n
 =
 6
3.
 H
yp
 =
 H
yp
er
ac
ti
vi
ty
; A
g
g
 =
 A
gg
re
ss
io
n
; A
n
x 
=
 A
n
xi
et
y;
 D
ep
 =
 D
ep
re
ss
io
n
; S
o
m
 =
 S
o
m
at
iz
at
io
n
; A
ty
 =
 A
ty
p
ic
al
it
y;
 W
it
 =
 W
it
h
d
ra
w
al
; A
tt
 =
 A
tt
en
ti
o
n
 P
ro
b
le
m
s;
 A
d
a 
=
 A
d
ap
ta
b
ili
ty
; 
S
o
c 
=
 S
o
ci
al
 S
ki
lls
; A
ct
 =
 A
ct
iv
it
ie
s 
of
 D
ai
ly
 L
iv
in
g;
 F
u
n
 =
 F
u
n
ct
io
n
al
 C
o
m
m
u
n
ic
at
io
n
; E
P
 =
 E
xt
er
n
al
iz
in
g 
P
ro
b
le
m
s;
 IP
 =
 In
te
rn
al
iz
in
g 
P
ro
b
le
m
s;
 A
S
 =
 A
d
ap
ti
ve
 S
ki
lls
; B
S
 =
 B
eh
av
io
ra
l S
ym
p
to
m
s 
In
d
ex
. 
C
o
rr
el
at
io
n
 c
o
effi
ci
en
ts
 a
re
 c
o
rr
ec
te
d
 fo
r 
va
ri
ab
ili
ty
 o
f A
B
A
S
-3
 s
ta
n
d
ar
d
iz
at
io
n
 s
am
p
le
 (
sc
al
ed
 s
co
re
 S
D
 =
 3
, s
ta
n
d
ar
d
 s
co
re
 S
D
 =
 1
5
) 
u
si
n
g 
G
u
ilf
o
rd
’s
 (
19
5
4
) 
fo
rm
u
la
. A
B
A
S
-3
 W
o
rk
 a
n
d
 M
o
to
r 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
s 
ar
e 
ex
cl
u
d
ed
 fr
o
m
 t
h
is
 t
ab
le
 b
ec
au
se
 o
f m
is
si
n
g 
d
at
a.
 B
A
S
C
-2
 m
ea
n
s 
an
d
 S
D
s 
ar
e 
b
as
ed
 o
n
 T
 s
co
re
s.
 O
n
 b
eh
av
io
ra
l p
ro
b
le
m
 s
ca
le
s 
(e
.g
., 
A
gg
re
ss
io
n
),
 h
ig
h
er
 T
 s
co
re
s 
in
d
ic
at
e 
gr
ea
te
r 
fr
eq
u
en
cy
 o
f 
p
ro
b
le
m
s;
 o
n
 p
os
it
iv
e 
b
eh
av
io
ra
l s
ca
le
s 
(e
.g
., 
S
o
ci
al
 S
ki
lls
),
 h
ig
h
er
 T
 s
co
re
s 
in
d
ic
at
e 
gr
ea
te
r 
fr
eq
u
en
cy
 o
f p
os
it
iv
e 
b
eh
av
io
rs
.
112 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.4
3.
 C
o
rr
el
at
io
n
 B
et
w
ee
n
 t
h
e 
B
A
S
C
-2
 a
n
d
 t
h
e 
A
B
A
S
-3
: T
ea
ch
er
 F
o
rm
B
A
S
C
-2
 B
eh
av
io
r 
S
ca
le
s
B
A
S
C
-2
 C
o
m
p
o
si
te
s
A
B
A
S
-3
H
yp
A
g
g
A
n
x
D
ep
S
o
m
A
ty
W
it
A
tt
A
d
a
S
o
c
A
ct
Fu
n
E
P
IP
B
S
A
S
M
ea
n
S
D
A
B
A
S
-3
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
–
0
.3
9
–
0
.3
4
–
0
.5
5
–
0
.5
7
–
0
.3
7
–
0
.1
4
–
0
.1
3
–
0
.0
4
0
.3
0
0
.2
9
0
.4
8
0
.5
3
–
0
.3
4
–
0
.5
9
–
0
.3
8
0
.4
3
4
.6
2
.8
C
o
m
m
u
n
it
y 
U
se
–
0
.2
3
–
0
.2
3
–
0
.5
5
–
0
.4
9
–
0
.2
9
–
0
.1
1
–
0
.1
7
0
.0
5
0
.3
0
0
.2
0
0
.2
3
0
.3
5
–
0
.1
6
–
0
.5
4
–
0
.2
7
0
.2
4
5.
2
3.
9
Fu
n
ct
io
n
al
 A
ca
d
em
ic
s
–
0
.2
9
–
0
.2
3
–
0
.4
3
–
0
.3
8
–
0
.2
4
–
0
.1
6
–
0
.1
9
–
0
.0
9
0
.2
9
0
.2
0
0
.3
0
0
.3
4
–
0
.2
2
–
0
.4
2
–
0
.3
2
0
.2
6
5.
4
3.
9
S
ch
o
o
l L
iv
in
g
–
0
.2
5
–
0
.2
0
–
0
.4
5
–
0
.3
9
–
0
.2
8
–
0
.1
1
–
0
.0
6
–
0
.0
2
0
.2
4
0
.2
9
0
.4
8
0
.4
8
–
0
.2
0
–
0
.4
5
–
0
.2
5
0
.4
0
5.
4
3.
2
H
ea
lt
h
 a
n
d
 S
af
et
y
–
0
.2
3
–
0
.2
0
–
0
.5
0
–
0
.4
1
–
0
.2
5
–
0
.0
5
–
0
.1
0
0
.0
8
0
.1
9
0
.2
8
0
.4
4
0
.3
5
–
0
.1
6
–
0
.4
7
–
0
.2
1
0
.3
6
5.5
3.
5
Le
is
u
re
–
0
.5
1
–
0
.4
8
–
0
.6
0
–
0
.6
8
–
0
.5
1
–
0
.1
8
–
0
.0
1
–
0
.1
0
0
.3
4
0
.3
0
0
.4
0
0
.5
0
–
0
.5
0
–
0
.6
8
–
0
.4
6
0
.4
0
5.
3
2
.4
S
el
f-
C
ar
e
–
0
.3
0
–
0
.2
1
–
0
.4
0
–
0
.3
7
–
0
.2
6
–
0
.1
3
–
0
.0
7
–
0
.0
1
0
.2
8
0
.2
0
0
.4
0
0
.2
7
–
0
.2
4
–
0
.4
0
–
0
.2
6
0
.2
6
6
.0
3.
6
S
el
f-
D
ir
ec
ti
o
n
–
0
.2
2
–
0
.1
9
–
0
.4
2
–
0
.3
1
–
0
.2
7
–
0
.0
7
–
0
.1
3
0
.0
4
0
.1
8
0
.2
9
0
.5
2
0
.4
3
–
0
.1
8
–
0
.4
0
–
0
.2
1
0
.4
2
5.
3
3.
0
S
o
ci
al
–
0
.3
1
–
0
.2
9
–
0
.5
0
–
0
.3
9
–
0
.2
8
–
0
.0
3
0
.0
0
0
.0
0
0
.3
2
0
.2
7
0
.3
9
0
.4
6
–
0
.2
8
–
0
.4
7
–
0
.2
4
0
.3
7
4
.9
2
.7
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
–
0
.3
0
–
0
.2
6
–
0
.4
7
–
0
.4
2
–
0
.2
9
–
0
.1
3
–
0
.1
7
–
0
.0
5
0
.2
9
0
.2
4
0
.4
3
0
.4
4
–
0
.2
5
–
0
.4
7
–
0
.3
2
0
.3
5
71
.7
16
.0
S
o
ci
al
–
0
.4
8
–
0
.4
6
–
0
.6
1
–
0
.6
1
–
0
.4
5
–
0
.1
2
0
.0
0
–
0
.0
8
0
.3
9
0
.3
3
0
.4
5
0
.5
3
–
0
.4
6
–
0
.6
4
–
0
.4
1
0
.4
3
75
.4
11
.6
P
ra
ct
ic
al
–
0
.3
1
–
0
.2
6
–
0
.5
3
–
0
.4
7
–
0
.3
2
–
0
.1
1
–
0
.1
0
–
0
.0
1
0
.3
1
0
.2
6
0
.4
5
0
.4
0
–
0
.2
5
–
0
.5
3
–
0
.3
0
0
.3
4
73
.6
16
.9
G
A
C
–
0
.3
5
–
0
.3
0
–
0
.5
5
–
0
.5
0
–
0
.3
4
–
0
.1
3
–
0
.1
1
–
0
.0
3
0
.3
2
0
.2
7
0
.4
6
0
.4
6
–
0
.2
9
–
0
.5
5
–
0
.3
4
0
.3
8
71
.6
15
.4
B
A
S
C
-2
M
ea
n
5
2
.9
4
6
.9
4
6
.1
4
8
.2
4
6
.9
5
4
.5
5
6
.2
5
4
.8
4
7.
6
4
2
.1
4
1.
7
4
1.
7
4
8
.9
4
6
.4
5
2
.9
4
1.
4
S
D
9.
0
8
.6
13
.6
8
.6
8
.4
10
.4
9.
7
6
.9
8
.2
10
.2
9.
9
10
.3
8
.4
11
.0
8
.1
8
.7
N
ot
e.
 n
 =
 6
3.
 H
yp
 =
 H
yp
er
ac
ti
vi
ty
; A
g
g
 =
 A
gg
re
ss
io
n
; A
n
x 
=
 A
n
xi
et
y;
 D
ep
 =
 D
ep
re
ss
io
n
; S
o
m
 =
 S
o
m
at
iz
at
io
n
; A
ty
 =
 A
ty
p
ic
al
it
y;
 W
it
 =
 W
it
h
d
ra
w
al
; A
tt
 =
 A
tt
en
ti
o
n
 P
ro
b
le
m
s;
 A
d
a 
=
 A
d
ap
ta
b
ili
ty
; 
S
o
c 
=
 S
o
ci
al
 S
ki
lls
; A
ct
 =
 A
ct
iv
it
ie
s 
of
 D
ai
ly
 L
iv
in
g;
 F
u
n
 =
 F
u
n
ct
io
n
al
 C
o
m
m
u
n
ic
at
io
n
; E
P
 =
 E
xt
er
n
al
iz
in
g 
P
ro
b
le
m
s;
 IP
 =
 In
te
rn
al
iz
in
g 
P
ro
b
le
m
s;
 A
S
 =
 A
d
ap
ti
ve
 S
ki
lls
; B
S
 =
 B
eh
av
io
ra
l S
ym
p
to
m
s 
In
d
ex
. 
C
o
rr
el
at
io
n
 c
o
effi
ci
en
ts
 a
re
 c
o
rr
ec
te
d
 fo
r 
va
ri
ab
ili
ty
 o
f A
B
A
S
-3
 s
ta
n
d
ar
d
iz
at
io
n
 s
am
p
le
 (
sc
al
ed
 s
co
re
 S
D
 =
 3
, s
ta
n
d
ar
d
 s
co
re
 S
D
 =
 1
5
) 
u
si
n
g 
G
u
ilf
o
rd
’s
 (
19
5
4
) 
fo
rm
u
la
. A
B
A
S
-3
 W
o
rk
 a
n
d
 M
o
to
r 
ad
ap
ti
ve
 s
ki
ll 
ar
ea
s 
ar
e 
ex
cl
u
d
ed
 fr
o
m
 t
h
is
 t
ab
le
 b
ec
au
se
 o
f m
is
si
n
g 
d
at
a.
 B
A
S
C
-2
 m
ea
n
s 
an
d
 S
D
s 
ar
e 
b
as
ed
 o
n
 T
 s
co
re
s.
 O
n
 b
eh
av
io
ra
l p
ro
b
le
m
 s
ca
le
s 
(e
.g
., 
A
gg
re
ss
io
n
),
 h
ig
h
er
 T
 s
co
re
s 
in
d
ic
at
e 
gr
ea
te
r 
fr
eq
u
en
cy
 o
f 
p
ro
b
le
m
s;
 o
n
 p
os
it
iv
e 
b
eh
av
io
ra
l s
ca
le
s 
(e
.g
., 
S
o
ci
al
 S
ki
lls
),
 h
ig
h
er
 T
 s
co
re
s 
in
d
ic
at
e 
gr
ea
te
r 
fr
eq
u
en
cy
 o
f p
os
it
iv
e 
b
eh
av
io
rs
.
ABAS-3 113Validity
Correlations With the Reynolds Intellectual 
Assessment Scales (RIAS)
The RIAS is an individually administered test of 
intelligence that yields four composite scores: Ver-
bal Intelligence (VIX), Nonverbal Intelligence (NIX), 
Composite Intelligence (CIX), and Composite Memory 
(CMX). The ABAS-3 clinical samples included a group 
of 24 children with intellectual disability (ID) whose 
diagnoses were based in part on their RIAS scores. 
These children ranged in age from 4 to 14 years, with 
a mean age of 10.7 years (SD = 2.9). Fifteen of the chil-
dren (62.5%) were boys. The sample was composed 
mostly of Black children (87.5%), from families with 
lower levels of head-of-household education (66.7% 
had a high school degree or less education).
Tables 5.44 and 5.45 present the results of two stud-
ies with this sample, one with ratings on the ABAS-3 
Parent Form, another with ratings on the Teacher 
Form. The intellectual functioning of this group was 
significantly below average (mean CIX standard score 
= 50.9; SD = 10.5). As would be expected, the adaptive 
skills of this group were in the low to extremely low 
range. On the ABAS-3 Parent Form, mean GAC was 
57.5 (SD = 6.7), and mean adaptive skill area scaled 
scores ranged from 2.1 (Functional Academics) to 
4.7 (Home Living). On the Teacher Form, mean GAC 
was 60.5 (SD = 11.1), and mean adaptive skill area 
scaled scores ranged from 1.8 (Functional Academics) 
to 4.0 (Leisure).
Table 5.44. Correlation Between the RIAS and the ABAS-3: Parent Form
RIAS ABAS-3
Verbal 
Intelligence (VIX)
Nonverbal 
Intelligence (NIX)
Composite 
Intelligence (CIX)
Composite 
Memory (CMX) Mean SD
ABAS-3
Adaptive skill area
Communication 0.66 0.68 0.74 0.78 3.1 1.5
Community Use 0.69 0.66 0.82 0.78 3.0 1.9
Functional Academics 0.83 0.67 0.88 0.87 2.1 1.5
Home Living 0.45 0.55 0.53 0.34 4.7 1.7
Health and Safety 0.68 0.82 0.85 0.82 3.3 1.7
Leisure 0.78 0.72 0.84 0.86 2.7 1.2
Self-Care 0.46 0.61 0.61 0.70 3.0 1.8
Self-Direction 0.78 0.76 0.88 0.82 2.4 1.3
Social 0.77 0.49 0.80 0.65 2.2 1.3
Adaptive domain
Conceptual 0.79 0.75 0.87 0.84 57.7 7.6
Social 0.85 0.76 0.89 0.84 61.4 5.8
Practical 0.77 0.85 0.89 0.86 61.7 7.3
GAC 0.83 0.83 0.91 0.88 57.5 6.7
RIAS
Mean 53.1 61.3 50.9 57.3
SD 12.3 12.5 10.5 13.0
Note. n = 24. Correlation coefficients are corrected for variability of ABAS-3 standardization sample (scaled score SD = 3, standard score SD = 15) 
using Guilford’s (1954) formula. ABAS-3 Work adaptive skill area is excluded from this table because of missing data.
114 ABAS-3 Chapter 5 Reliability and Validity
Table 5.45. Correlation Between the RIAS and the ABAS-3: Teacher Form
RIAS ABAS-3
Verbal 
Intelligence (VIX)
Nonverbal 
Intelligence (NIX)
Composite 
Intelligence (CIX)
Composite 
Memory (CMX) Mean SD
ABAS-3
Adaptive skill area
Communication 0.45 0.02 0.24 0.31 2.9 2.0
Community Use 0.49 0.30 0.50 0.40 2.9 2.5
Functional Academics 0.61 0.42 0.66 0.55 1.8 2.2
School Living 0.31 –0.01 0.14 0.12 3.6 2.7
Health and Safety 0.29 0.22 0.28 0.42 3.7 2.5
Leisure 0.49 0.29 0.51 0.69 4.0 1.9
Self-Care 0.34 0.28 0.35 0.51 3.5 2.7
Self-Direction 0.47 0.26 0.42 0.48 3.3 2.2
Social 0.38 –0.03 0.21 0.17 3.5 2.7
Adaptive domain
Conceptual 0.66 0.36 0.62 0.59 59.0 9.7
Social 0.52 0.07 0.38 0.47 69.4 9.8
Practical 0.43 0.23 0.37 0.42 62.4 12.0
GAC 0.54 0.26 0.48 0.50 60.5 11.1
RIAS
Mean 53.1 61.3 50.9 57.3
SD 12.3 12.5 10.5 13.0
Note. n = 24. Correlation coefficients are corrected for variability of ABAS-3 standardization sample (scaled score SD = 3, standard score SD = 15) 
using Guilford’s (1954) formula. ABAS-3 Work adaptive skill area is excluded from this table because of missing data.
The ABAS-II manual documented moderate correla-
tions between the ABAS-II scores and a range of tests 
of intelligence and cognitive ability (summarized 
below). The parent-rated ABAS-3 scores correlated 
strongly with the RIAS scores, with an average r of .75 
across all pairs of scores. Parent-rated GAC correlated 
at .91 with RIAS CIX. On the ABAS-3 Teacher Form, 
correlations with RIAS scores were mostly in the 
moderate range (average r = .37). Teacher-rated GAC 
correlated at .48 with RIAS CIX. In support of this 
model, a body of research has found mostly moderate 
relationships between measures of adaptive behavior 
and intelligence tests (see Boan & Harrison, 1997).
These correlations were higher than expected, as 
correlations between the ABAS-II and variousen
cy
 R
el
ia
b
ili
ty
 C
o
effi
ci
en
ts
 a
n
d
 S
E
M
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
as
, A
d
ap
ti
ve
 D
o
m
ai
n
s,
 a
n
d
 t
h
e 
G
A
C
: 
S
ta
n
d
ar
d
iz
at
io
n
 S
am
p
le
 b
y 
A
ge
 G
ro
u
p
: P
ar
en
t 
Fo
rm
 (
A
ge
s 
5
–
2
1)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/
 
C
o
m
p
o
si
te
A
ge
 g
ro
u
p
 (
in
 y
ea
rs
)
5
 
(n
 =
 1
79
)
6
 
(n
 =
 1
9
5
)
7 
(n
 =
 1
9
2
)
8
 
(n
 =
 1
6
7)
9
 
(n
 =
 1
6
6
)
10
 
(n
 =
 1
5
8
)
11
 
(n
 =
 1
3
5
)
12
 
(n
 =
 1
4
1)
13
–
14
 
(n
 =
 2
0
3
)
15
–
16
 
(n
 =
 1
9
7)
17
–
2
1 
(n
 =
 1
3
8
)
A
ve
ra
ge
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r x
x
S
E
M
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
0
.9
1
0
.8
8
0
.9
0
0
.9
5
0
.9
2
0
.8
2
0
.8
9
0
.9
8
0
.9
1
0
.9
2
0
.9
4
0
.7
5
0
.9
0
0
.9
3
0
.9
6
0
.6
2
0
.9
8
0
.4
3
0
.9
7
0
.5
1
0
.9
3
0
.8
1
0
.9
4
0
.8
0
C
o
m
m
u
n
it
y 
U
se
0
.9
4
0
.7
6
0
.9
2
0
.8
4
0
.9
3
0
.7
7
0
.9
3
0
.8
2
0
.9
1
0
.8
8
0
.9
2
0
.8
5
0
.9
2
0
.8
2
0
.9
2
0
.8
5
0
.8
9
0
.9
7
0
.9
4
0
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1
0
.9
6
0
.6
4
0
.9
3
0
.8
1
Fu
n
ct
io
n
al
 A
ca
d
em
ic
s
0
.9
4
0
.7
3
0
.9
3
0
.8
2
0
.9
3
0
.8
0
0
.9
1
0
.8
8
0
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0
0
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3
0
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1
0
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1
0
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8
1.
0
2
0
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2
0
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4
0
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2
0
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3
0
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4
0
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3
0
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5
0
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9
0
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2
0
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4
H
o
m
e 
Li
vi
n
g
0
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4
0
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6
0
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3
0
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1
0
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4
0
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3
0
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4
0
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3
0
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4
0
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5
0
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4
0
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6
0
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3
0
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9
0
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5
0
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9
0
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5
0
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7
0
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6
0
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6
0
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5
0
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6
0
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4
0
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2
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.8
6
1.
12
0
.8
6
1.
12
0
.8
7
1.
0
7
0
.8
1
1.
3
2
0
.8
2
1.
2
8
0
.8
6
1.
12
0
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2
1.
27
0
.9
2
0
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7
0
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5
0
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9
0
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4
0
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4
0
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2
0
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6
0
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9
1.
0
6
Le
is
u
re
0
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4
0
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4
0
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1
0
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8
0
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2
0
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3
0
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1
0
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1
0
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0
0
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3
0
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3
0
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0
0
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9
1.
0
1
0
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4
0
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4
0
.9
7
0
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2
0
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5
0
.6
7
0
.9
4
0
.7
6
0
.9
3
0
.8
1
S
el
f-
C
ar
e
0
.9
1
0
.9
2
0
.8
7
1.
0
9
0
.8
9
0
.9
9
0
.8
8
1.
0
4
0
.8
9
1.
0
0
0
.9
1
0
.8
8
0
.8
4
1.
2
1
0
.9
5
0
.6
8
0
.9
7
0
.4
8
0
.9
7
0
.5
3
0
.9
1
0
.8
9
0
.9
2
0
.9
1
S
el
f-
D
ir
ec
ti
o
n
0
.9
3
0
.8
1
0
.9
3
0
.8
0
0
.9
5
0
.6
8
0
.9
5
0
.6
7
0
.9
4
0
.7
2
0
.9
4
0
.7
1
0
.9
5
0
.7
0
0
.9
6
0
.5
9
0
.9
7
0
.5
5
0
.9
7
0
.4
9
0
.9
6
0
.6
0
0
.9
5
0
.6
7
S
o
ci
al
0
.9
4
0
.7
3
0
.9
4
0
.7
3
0
.9
5
0
.6
5
0
.9
2
0
.8
5
0
.9
5
0
.6
9
0
.9
5
0
.6
5
0
.9
3
0
.8
0
0
.9
5
0
.6
5
0
.9
8
0
.4
2
0
.9
7
0
.5
4
0
.9
4
0
.7
0
0
.9
5
0
.6
8
W
o
rk
—
—
—
—
—
—
 —
—
—
—
—
—
—
—
—
—
—
—
—
—
0
.9
9
0
.2
1
0
.9
9
0
.2
1
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.9
7
2
.7
3
0
.9
6
2
.8
3
0
.9
7
2
.5
5
0
.9
6
2
.8
8
0
.9
6
2
.9
8
0
.9
6
2
.8
3
0
.9
6
3.
10
0
.9
8
2
.3
5
0
.9
8
2
.0
2
0
.9
8
1.
9
5
0
.9
8
2
.1
9
0
.9
7
2
.6
1
S
o
ci
al
0
.9
7
2
.7
5
0
.9
6
3.
0
6
0
.9
7
2
.7
7
0
.9
5
3.
3
3
0
.9
6
3.
15
0
.9
6
2
.8
2
0
.9
4
3.
5
8
0
.9
7
2
.7
0
0
.9
9
1.
8
3
0
.9
8
2
.3
5
0
.9
7
2
.7
8
0
.9
7
2
.8
6
P
ra
ct
ic
al
 (
w
it
h
o
u
t 
W
o
rk
)
0
.9
7
2
.6
4
0
.9
6
2
.8
5
0
.9
7
2
.6
4
0
.9
6
2
.8
8
0
.9
6
2
.9
2
0
.9
7
2
.6
8
0
.9
6
3.
16
0
.9
8
2
.3
3
0
.9
8
2
.1
9
0
.9
8
1.
8
9
0
.9
8
2
.1
5
0
.9
7
2
.6
0
G
A
C
 (
w
it
h
o
u
t 
W
o
rk
)
0
.9
9
1.
72
0
.9
8
1.
8
5
0
.9
9
1.
6
5
0
.9
8
1.
8
9
0
.9
8
1.
9
0
0
.9
9
1.
75
0
.9
8
2
.0
5
0
.9
9
1.
5
0
0
.9
9
1.
3
0
0
.9
9
1.
2
5
0
.9
9
1.
4
1
0
.9
9
1.
6
8
N
ot
e.
 A
ve
ra
ge
 r
el
ia
b
ili
ty
 c
o
effi
ci
en
ts
 (
r x
x
) 
w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
Fi
sh
er
’s
 z
 t
ra
n
sf
o
rm
at
io
n
. A
d
ap
ti
ve
 d
o
m
ai
n
 a
n
d
 G
A
C
 r
el
ia
b
ili
ti
es
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
th
e 
fo
rm
u
la
 fo
r 
re
lia
b
ili
ty
 o
f l
in
ea
r 
co
m
b
in
at
io
n
s 
u
si
n
g 
th
e 
su
m
 o
f t
h
e 
st
an
d
ar
d
 s
co
re
s 
(N
u
n
n
al
ly
 &
 B
er
n
st
ei
n
, 1
9
9
4
).
 A
ve
ra
ge
 S
E
M
s 
w
er
e 
ca
lc
u
la
te
d
 b
y 
av
er
ag
in
g 
th
e 
su
m
 o
f t
h
e 
sq
u
ar
ed
 S
E
M
s 
fo
r 
ea
ch
 a
ge
 g
ro
u
p
 a
n
d
 o
b
ta
in
in
g 
th
e 
sq
u
ar
e 
ro
o
t 
of
 t
h
e 
re
su
lt
.
70 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.3
. I
n
te
rn
al
 C
o
n
si
st
en
cy
 R
el
ia
b
ili
ty
 C
o
effi
ci
en
ts
 a
n
d
 S
E
M
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
as
, A
d
ap
ti
ve
 D
o
m
ai
n
s,
 a
n
d
 t
h
e 
G
A
C
: 
S
ta
n
d
ar
d
iz
at
io
n
 S
am
p
le
 b
y 
A
ge
 G
ro
u
p
: T
ea
ch
er
/D
ay
ca
re
 P
ro
vi
d
er
 F
o
rm
 (
A
ge
s 
2
–
5
)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/
 
C
o
m
p
o
si
te
A
ge
 g
ro
u
p
 (
in
 y
ea
rs
 a
n
d
 m
o
n
th
s)
2
:0
–
2
:5
 
(n
 =
 5
7)
2
:6
–
2
:1
1 
(n
 =
 6
3
)
3
:0
–
3
:5
 
(n
 =
 6
1)
3
:6
–
3
:1
1 
(n
 =
 9
0
)
4
:0
–
4
:5
 
(n
 =
 1
0
8
)
4
:6
–
4
:1
1 
(n
 =
 1
2
1)
5
:0
–
5
:1
1 
(n
 =
 1
57
)
A
ve
ra
ge
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r x
x
S
E
M
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
0
.9
4
0
.7
2
0
.9
4
0
.7
4
0
.9
6
0
.6
3
0
.8
2
1.
2
8
0
.9
1
0
.8
8
0
.9
5
0
.7
0
0
.9
7
0
.5
2
0
.9
4
0
.8
1
Fu
n
ct
io
n
al
 P
re
-A
ca
d
em
ic
s
0
.9
4
0
.7
1
0
.9
3
0
.7
8
0
.9
2
0
.8
6
0
.9
0
0
.9
5
0
.9
2
0
.8
7
0
.9
4
0
.7
3
0
.9
6
0
.6
2
0
.9
3
0
.8
0
S
ch
o
o
l L
iv
in
g
0
.9
3
0
.8
0
0
.9
3
0
.8
2
0
.9
5
0
.6
5
0
.9
1
0
.9
0
0
.9
0
0
.9
5
0
.9
3
0
.8
0
0
.9
7
0
.5
2
0
.9
4
0
.7
9
H
ea
lt
h
 a
n
d
 S
af
et
y
0
.8
6
1.
14
0
.8
9
0
.9
9
0
.9
1
0
.9
1
0
.8
0
1.
3
5
0
.8
4
1.
2
1
0
.8
8
1.
0
4
0
.9
3
0
.8
0
0
.8
8
1.
0
8
Le
is
u
re
0
.8
3
1.
24
0
.9
0
0
.9
7
0
.9
4
0
.7
6
0
.8
7
1.
0
8
0
.9
2
0
.8
5
0
.9
1
0
.8
9
0
.9
5
0
.6
5
0
.9
1
0
.9
4
S
el
f-
C
ar
e
0
.8
1
1.
3
1
0
.8
7
1.
0
8
0
.9
5
0
.7
0
0
.7
2
1.
59
0
.8
7
1.
0
7
0
.9
2
0
.8
4
0
.9
6
0
.5
9
0
.8
9
1.
0
8
S
el
f-
D
ir
ec
ti
o
n
0
.9
0
0
.9
6
0
.9
3
0
.8
1
0
.9
4
0
.7
1
0
.8
8
1.
0
5
0
.9
4
0
.7
5
0
.9
3
0
.8
1
0
.9
6
0
.6
3
0
.9
3
0
.8
3
S
o
ci
al
0
.9
1
0
.9
1
0
.9
3
0
.7
8
0
.9
5
0
.6
4
0
.8
8
1.
0
5
0
.9
4
0
.7
4
0
.9
4
0
.7
5
0
.9
7
0
.5
6
0
.9
4
0
.7
9
M
o
to
r
0
.8
8
1.
0
4
0
.8
6
1.
11
0
.9
5
0
.7
0
0
.8
2
1.
27
0
.8
4
1.
2
0
0
.9
1
0
.8
8
0
.9
7
0
.5
4
0
.9
1
0
.9
9
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.9
7
2
.7
5
0
.9
7
2
.5
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were generally in the moderate range. The most likely 
reason is the small RIAS sample documented here, 
consisting mostly of very low-functioning individu-
als, which would inflate the correlation coefficients 
because of the restricted range of scores.
ABAS-II Concurrent Validity Studies
The following section summarizes correlations with 
other measures reported in the ABAS-II manual 
(Harrison & Oakland, 2003). Because of the very 
high level of similarity in the item content between 
ABAS-II and ABAS-3, these earlier studies provide 
validity evidence that is relevant to the ABAS-3.
Scales of Independent Behavior–Revised (SIB-R)
Relationships between the ABAS-II and two forms of 
the SIB-R (Early Development Form and Short Form) 
were investigated in a sample of children ranging 
from 2 months to 23 months old. One purpose of this 
study was to determine how a more limited assess-
ment such as the SIB-R Short Form may relate to the 
more comprehensive, detailed measures provided 
by the ABAS-II. SIB-R Short Form results used in 
those studies had relatively low correlations with the 
ABAS-II compared with prior studies with the Vine-
land, another comprehensive measure of adaptive 
behavior. The SIB-R Early Development Form Broad 
ABAS-3 115Validity
Independence standard score correlated at .18 with 
the GAC, and also had low correlations with the adap-
tive domains and adaptive skill areas. The correlation 
between the GAC and the SIB-R Broad Independence 
standard score was .59.
Wechsler Preschool and Primary Scale of 
Intelligence–Third Edition (WPPSI-III)
Correlations between the ABAS-II and the WPPSI-III 
were investigated using two samples of children ages 
2 to 6. In Sample 1, ABAS-II GAC correlated at .61 with 
WPPSI-III Full Scale IQ (FSIQ). Correlations between 
GAC and WPPSI-III Verbal IQ (VIQ), Performance 
IQ (PIQ), and General Language Composite (GLC) 
were .62, .50, and .57, respectively. The FSIQ scores of 
the WPPSI-III showed the highest correlations with 
the ABAS-II Conceptual adaptive domain (.63) and 
Functional Pre-Academics adaptive skill area (.60). 
In addition, WPPSI-III VIQ correlated at .65 with 
the Conceptual adaptive domain. In Sample 2, GAC 
correlated at .54 with WPPSI-III FSIQ. Correlations 
between GAC and WPPSI-III scores were .51, .48, and 
.47 for VIQ, PIQ, and GLC, respectively. As in Sample 
1, FSIQ showed the highest correlations with ABAS-II 
Conceptual adaptive domain (.60) and Functional 
Pre-Academics adaptive skill area (.62). Also similar 
to Sample 1, WPPSI-III VIQ correlated at .58 with 
the Conceptual adaptive domain. Overall, the cor-
relations between the WPPSI-III and ABAS-II parent 
ratings were moderate, and slightly lower than those 
of ABAS-II teacher ratings. Results from both samples 
suggest generally moderate levels of correlation 
between ABAS-II scores and WPPSI-III IQ scores.
Wechsler Intelligence Scale for Children–Fourth 
Edition (WISC-IV)
Correlations between the ABAS-II and the WISC-IV were 
investigated using two samples of children ages 6 to 16. 
In Sample 1, GAC correlated at .41 with WISC-IV FSIQ. 
The correlations of GAC with VCI and PRI were .39 
and .30, respectively. The FSIQ scores of the WISC-IV 
correlated most highly with ABAS-II Conceptual adap-
tive domain (.49) and the Communication adaptive 
skill area (.54). In Sample 2, WISC-IV FSIQ correlated at 
.58 with GAC. Correlations between GAC and WISC-IV 
VCI and PRI were .42 and .39, respectively. As expected, 
ABAS-II Conceptual adaptive domain and the Func-
tional Academics adaptive skill area displayed the 
highest correlations with WISC-IV FSIQ, at .63 and .57 
respectively. Overall results suggest moderate levels of 
correlation between GAC and the WISC-IV scores.
Wechsler Adult Intelligence Scale–Third 
Edition (WAIS-III)
Relationships between the ABAS-II and the WAIS-III 
were evaluated by administering the WAIS-III to a 
group of adults ages 16 to 71 who also rated themselves 
using the ABAS-II Adult Form. ABAS-II GAC corre-
lated at .67 with WAIS-III FSIQ. WAIS-III VIQ and PIQ 
correlated at .72 and .50, respectively, with GAC. Cor-
relations between the WAIS-III FSIQ and the ABAS-II 
adaptive domains generally were in the .40s and .50s. 
Correlations between the WAIS-III FSIQ and the ABAS-II 
adaptive skill areas generally were in the .40s.
Wechsler Abbreviated Scale of Intelligence (WASI)
Relationships between the ABAS-II and the WASI were 
evaluated by administering the WASI to a sample of 
individuals ages 7 to 21 who were also rated with the 
ABAS-II Parent Form. The GAC correlated at .42 with 
the WASI four-subtest FSIQ, and correlated at .32, 
.43, and .39 with the WASI VIQ, PIQ, and two-subtest 
FSIQ, respectively. These results suggest a moderate 
relationship between scores from the ABAS-II and 
those from the WASI.
Stanford-Binet Intelligence Scales, Fourth 
Edition (SB4)
Correlations between the ABAS-II and the SB4 were 
evaluated with a mixed clinical sample of children 
of ages 6 to 21 who had diagnoses of autistic disor-
der (15%) and intellectual disability (85%). These 
children were administered the SB4 and were also 
rated with the ABAS-II Teacher Form. Mean scores 
were 51 on SB4 Standard Age Score (SAS) and 61 on 
ABAS-II GAC. The correlation between GAC and SB4 
SAS was .39. Among individual ABAS-II scores, the 
Social adaptive domain showed the highest correla-
tion (.73) with the SB4 SAS. This pattern of correlation 
was expected with this sample, because it consisted 
primarily of individuals with intellectual disability 
whose range of scores on the ABAS-II Conceptual 
adaptive domain was significantly more restricted 
than the range of scores on the Social adaptive 
domain.
Wechsler Individual Achievement Test (WIAT)
Correlations between the ABAS-II and the WIAT were 
examined in a mixed clinical sample of children 
ranging ages 7 to 15 who were diagnosed with intel-
lectual disability (68%), learning disabilities (18%), 
ADHD (9%), and speech–language impairments (5%). 
116 ABAS-3 Chapter 5 Reliability and Validity
The sample was administered the WIAT and rated 
using the ABAS-II Teacher Form. Correlations 
between GAC and the four WIAT composites were as 
follows: Numerical Operations, .63; Math Reasoning, 
.52; Reading Comprehension, .46; and Basic Read-
ing, .39. The Conceptual, Social, and Practical adap-
tive domains correlated most highly with Numerical 
Operations (.67, .68, and .67, respectively). Overall 
correlations between the ABAS-II and the WIAT were 
moderate in this mixed clinical sample.
Validity Evidence Based on Clinical 
Groups
In addition to correlations with other measures, the 
construct validity of the ABAS-3 is supported by its 
ability to distinguish between individuals with and 
without clinical disorders. Building on the extensive 
clinical samples reported in the ABAS-II manual 
(summarized below), the ABAS-3 research base 
includes new clinical studies on individuals with 
autism spectrum disorder (ASD), intellectual disabil-
ity (ID), and attention-deficit/hyperactivity disorder 
(ADHD). These three diagnostic groups were chosen 
because they collectively comprise a large proportion 
of children, adolescents, and adults referred for adap-
tive behavior assessment in schools and clinics.
Individuals in the ID groups were classified via scores 
from tests of intellectual ability. Each case in the sam-
ple had at least one score on a composite measure of 
intelligence that was at least 2 SD below the mean. A 
variety of intelligence and cognitive ability tests were 
used to classify the ID sample, including the WISC-IV, 
WPPSI-R, RIAS, Battelle Developmental Inventory, 
Bayley-III, KABC-II, and Stanford-Binet.
Students were selected for the ADHD groups based 
on the clinical judgment of the ABAS-3 clinical study 
coordinators, using some or all of the following 
information: prior clinical or IEP-based diagnosis of 
ADHD, scores reflecting significant ADHD symptomsfrom the Conners Comprehensive Behavior Rating 
Scales (Conners CBRS), the BASC, or other behavior 
rating scales, and ADHD-related treatment status 
(i.e., receiving behavioral interventions and/or stimu-
lant medication).
Individuals in the ASD groups had received a diag-
nosis of autism spectrum disorder from a clinical 
psychologist or a psychiatrist, or such diagnosis had 
been documented in the records associated with a 
special education eligibility decision. Each case also 
had test scores consistent with ASD from one or more 
of the following published autism measures: Autism 
Diagnostic Observation Schedule (first or second edi-
tion); Autism Diagnostic Interview, Revised (ADI-R); 
Social Communication Questionnaire (SCQ); Child-
hood Autism Rating Scale, Second Edition (CARS-2); 
Gilliam Autism Rating Scale (GARS-2); or Krug 
Asperger’s Disorder Index (KADI).
Unlike the large, demographically representative 
ABAS-3 standardization samples, these clinical 
groups are smaller, less broadly representative 
samples collected by clinicians in a variety of settings. 
Clinicians selected individuals who met diagnostic 
criteria. Data from these samples are presented as 
examples and are not intended to be definitive rep-
resentations of the diagnostic groups. The purpose of 
these clinical validity studies is to demonstrate that 
the ABAS-3 can provide a valid assessment of adap-
tive behavior for these diagnostic groups. It is impor-
tant to keep these factors in mind when evaluating 
the study results presented in this section.
Each clinical sample was compared to a matched 
control group of nonclinical cases drawn from the 
appropriate standardization sample. Each clinical 
case was matched to a nonclinical case on age, gen-
der, and ethnicity. The control cases were randomly 
selected from among subgroups in the standardiza-
tion sample that met the matching criteria.
Multivariate analysis of variance (MANOVA) was 
used to compare each clinical group to its matching 
control group on ABAS-3 adaptive skill area, adap-
tive domain, and GAC scores. In all comparisons, 
the MANOVA yielded a significant omnibus effect, 
indicating that the ABAS-3 scores, taken together, 
are lower in the clinical groups than in their match-
ing control groups.2 This finding is consistent with 
expectations that individuals with clinical disorders 
will show poorer adaptive skills than their typically 
developing peers. Of greater importance than statisti-
cally significant differences, however, are clinically 
meaningful differences, reflected in effect sizes and a 
pattern of score differences that comports with theo-
retical expectations.
2 The results of the omnibus tests (based on Wilks’ lambda) are presented in the notes to Tables 5.46 to 5.56.
ABAS-3 117Validity
Children With Autism Spectrum Disorder
Children with autism spectrum disorder (ASD) are 
characterized by deficits in verbal and nonverbal 
communication, social interaction, and restricted and 
repetitive behavior patterns (DSM-5, 2012). Several 
adaptive skill areas assessed by the ABAS-3, including 
communication, social competence, play/leisure, and 
self-care, are frequently addressed in treatment of 
children with ASD.
The ABAS-3 research base includes two samples of 
children with ASD. The first is a sample of 51 pre-
school-age children who were rated on the Parent/
Primary Caregiver and Teacher/Daycare Provider 
forms. These children ranged in age from 24 to 71 
months, with a mean age of 54.0 months (SD = 11.2). 
Thirty-five (68.6%) of the children were boys. The eth-
nic composition of the sample was 76.5% White, 9.8% 
Black, 9.8% Hispanic, and 3.9% other ethnicities. In 
terms of head-of-household education level (socio-
economic status), 37.3% of the sample had a 4-year 
college degree or higher, and 17.7% had a high-school 
degree or less.
The second ASD sample consisted of 37 school-age 
children and adolescents rated with the Parent and 
Teacher forms. The mean age of this group was 
10.6 years (SD = 4.0), ranging from 5 to 20 years of 
age. Twenty-seven (73.0%) of the children were boys. 
The ethnic composition of the sample was 75.7% White, 
18.9% Black, 2.7% Hispanic, and 2.7% other ethnici-
ties. In terms of head-of-household education level, 
67.6% of the sample had a 4-year college degree or 
higher, and 2.7% had a high-school degree or less.
The results of the comparisons between these 
clinical samples and their corresponding matched 
control groups are presented in Tables 5.46 through 
5.49. For the Parent/Primary Caregiver Form data, 
mean GAC for the ASD group was 60.0 (SD = 9.0), 
and mean GAC for the matched control group was 
103.0 (SD = 11.0). For the Parent Form data, mean 
GAC for the ASD group was 74.4 (SD = 14.0), and 
mean GAC for the matched control group was 99.2 
(SD = 16.1). For the Teacher/Daycare Form data, 
mean GAC for the ASD group was 62.4 (SD = 14.6), 
and mean GAC for the matched control group was 
100.6 (SD = 13.9). For the Teacher Form data, mean 
GAC for the ASD group was 75.8 (SD = 13.6), and 
mean GAC for the matched control group was 102.6 
(SD = 17.1).
The tables show that the ABAS-3 adaptive skill area 
scaled scores, adaptive domain standard scores, 
and GAC scores can differentiate between children 
with ASD and their typically developing peers, with 
robust and clinically meaningful effect sizes. Across 
all score comparisons, mean effect sizes were as fol-
lows: Teacher/Daycare Provider Form = 2.41; Parent/
Primary Caregiver Form = 2.51; Teacher Form = 1.52; 
Parent Form = 1.48. These results are consistent with 
the expectation that individuals with ASD show wide-
ranging impairments in adaptive behavior skills.
Children With Intellectual Disability
According to the AAIDD (2010), IDEA (2004), and 
DSM-5 (APA, 2013), intellectual disability (ID) is 
defined by impairment in both intelligence and 
adaptive behavior. Standardized assessment of adap-
tive function is thus a key element of diagnosing ID. 
Previous editions of the ABAS have been used exten-
sively to help identify ID and mental retardation, and 
to describe the adaptive strengths and challenges of 
individuals with these conditions.
The ABAS-II manual included studies of children 
with mild and moderate mental retardation, as 
well as a separate sample of children with Down 
syndrome. The ABAS-3 builds on this foundation 
of validity evidence with several new samples of 
individuals with ID, including a group of 21 pre-
school-aged children who were rated on the Parent/
Primary Caregiver Form. These children ranged 
in age from 2 to 68 months, with a mean age of 
39.3 months (SD = 22.4). Twelve (57.1%) of the children 
were boys. The sample was about two-thirds White, 
and about half of the households had at least one 
parent with a 4-year college degree or higher.
A second ID sample consisted of 28 school-age chil-
dren and adolescents rated with the ABAS-3 Parent 
and Teacher forms. The mean age of this group was 
10.8 years (SD = 3.3), ranging from 5 to 19 years. Eigh-
teen (64.3%) of the children were boys. Most of the 
children in this sample (78.6%) were African Ameri-
can, with the remaining 21.4% other ethnicities. This 
was predominantly a lower-SES sample, with only 
about 10% of the heads-of-household having a 4-year 
college degree or higher, and about 61% a high-
school degree or less.
118 ABAS-3 Chapter 5 Reliability and Validity
The results of the analyses of the ID groups are pre-
sented in Tables 5.50 through 5.52. For the Parent/
Primary Caregiver Form data, mean GAC for the ID 
group was 67.9 (SD = 11.4), and mean GAC for the 
matched control group was 99.9 (SD = 11.8). For the 
Parent Form data, mean GAC for the ID group was 
58.2 (SD = 7.8), and mean GAC for the matched con-
trol group was 94.1 (SD = 13.3). For the Teacher Form 
data, mean GAC for the ID group was 61.2 (SD = 12.4), 
and mean GAC for the matched control group was 
97.3 (SD = 13.6).
In addition to these samples,a small number (n = 11) 
of the Teacher/Daycare Provider Form were collected 
on a group of 4- to 5-year-olds (7 boys, 4 girls) diag-
nosed with ID. In this group, the average scaled score 
across all nine adaptive skill areas was 4.3 (average 
SD = 1.67), with mean scaled scores on the individual 
adaptive skill areas ranging from 2.6 (Social) to 6.6 
(Self-Care). The mean Composite standard scores 
were 64.3 (SD = 10.0) for the Conceptual adaptive 
domain, 62.6 (SD = 7.3) for the Social adaptive domain, 
and 65.0 (SD = 8.6) for the Practical adaptive domain. 
The mean GAC was 63.6 (SD = 8.6). These scores 
are comparable to those from the Parent/Primary 
Caregiver Form obtained from the ID sample (see 
Table 5.50).
Taken together, these studies demonstrate that the 
ABAS-3 adaptive skill area scaled scores, adaptive 
domain standard scores, and GAC scores can reliably 
differentiate children and adolescents with ID from 
their typically developing peers. ABAS-3 scores were 
consistently higher in the matched control groups, 
with uniformly large effect sizes. Across all score com-
parisons, mean effect sizes were as follows: Parent/
Primary Caregiver Form = 2.26; Teacher Form = 2.45; 
Parent Form = 2.91. Although these ID groups were 
not stratified according to severity of intellectual 
impairment, score differences of 2 SDs or greater 
were observed in almost every adaptive skill area 
across three forms. These score gaps are consistent 
with a large, finely differentiated scale of measure-
ment separating the ID and typically developing 
groups, a scale that may therefore be useful in iden-
tifying mild, moderate, and severe levels of adaptive 
impairment.
ABAS-3 119Validity
Table 5.46. Mean ABAS-3 Scaled and Composite Scores, Individuals With 
Autism Spectrum Disorder (ASD) and Matched Control Groups: 
Parent/Primary Caregiver Form (Ages 0–5)
Children with ASD Matched control group
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d
Adaptive skill area
Communication 3.4 3.1 10.5 2.2 2.67
Community Use 3.7 2.8 10.0 2.9 2.25
Functional Pre-Academics 4.9 3.6 10.7 2.7 1.82
Home Living 4.9 3.0 10.8 2.5 2.13
Health and Safety 4.5 2.6 10.7 2.7 2.38
Leisure 4.9 2.7 11.1 1.8 2.70
Self-Care 5.0 3.1 11.1 2.3 2.28
Self-Direction 5.2 2.3 10.6 2.4 2.30
Social 4.0 3.0 10.5 2.2 2.46
Motor 7.0 2.3 11.2 2.4 1.79
Adaptive domain
Conceptual 69.9 14.1 103.8 10.9 2.71
Social 70.3 14.2 104.0 9.8 2.81
Practical 69.9 13.6 103.0 12.0 2.59
GAC 60.0 9.0 103.0 11.0 4.31
Note. n = 49. Wilks’ lambda = .068, F(14, 82) = 80.30, pWith Attention-Deficit/Hyperactivity 
Disorder
Although adaptive skill deficits are not included in 
the diagnostic criteria for attention-deficit/hyperac-
tivity disorder (ADHD), the symptoms of this disorder 
often cause difficulties with daily functioning. Effec-
tive treatment of ADHD requires specific interven-
tions to improve adaptive skills, along with measures 
designed to reduce the behavioral symptoms of inat-
tentiveness, impulsiveness, and excessive activity.
The ABAS-3 clinical studies include a combined sample 
of 21 children and adolescents with ADHD, ranging in 
age from 4 to 16 years (M = 9.1 years, SD = 3.8). Com-
parison of scaled and standard scores allowed the 
inclusion of both preschool and school-age ABAS-3 
forms in the same analysis. The combined ADHD 
sample was evenly divided between boys and girls. 
The sample was 52.4% White, 23.8% Black, 9.5% 
Hispanic, and 14.3% other ethnicities. In terms of 
head-of-household education level, 19.0% of the 
sample had a 4-year college degree or higher, and 
38.1% had a high-school degree or less. Teacher-rated 
ABAS-3 forms were available on all 21 individuals in 
the sample, and parent-rated forms were available on 
17 individuals.
The analysis summarized in Tables 5.53 and 5.54 
compares the parent- and teacher-rated ABAS-3 
scores of the combined ADHD sample with scores 
from a matched control group. On the parent-
rated forms, mean GAC of the ADHD group was 82.7 
(SD = 14.8), and mean GAC of the control group was 
103.2 (SD = 10.5). On the teacher-rated forms, mean 
GAC of the ADHD group was 80.9 (SD = 7.6), and 
mean GAC of the control group was 99.8 (SD = 16.1). 
The mean effect sizes associated with these compari-
sons were 1.25 for the parent-rated forms and 1.20 for 
the teacher-rated forms.
Across the ABAS-3 scores, the effect sizes represent 
large and clinically meaningful differences in adap-
tive functioning between children and adolescents 
with ADHD and their typically developing peers. The 
effect sizes in the ADHD samples were not as large as 
those in the ID sample, which is to be expected, given 
that deficits in adaptive skills form part of the diag-
nostic criteria for ID. Of note is that the effect size for 
the Self-Direction adaptive skill area was one of the 
largest, for both parent-rated (1.71) and teacher-rated 
(1.53) forms. The Self-Direction items tap the ability 
to maintain attention and regulate impulsivity, two 
facets of behavior that are usually compromised in 
children with ADHD.
124 ABAS-3 Chapter 5 Reliability and Validity
Table 5.53. Mean ABAS-3 Scaled and Composite Scores, Combined ADHD 
Samples and Matched Control Groups: Parent/Primary Caregiver 
Form (Ages 0–5) and Parent Form (Ages 5–21)
Children with ADHD Matched control group
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d
Adaptive skill area
Communication 6.5 2.5 9.8 1.3 1.74
Community Use 8.8 1.9 10.4 2.5 0.70
Functional (Pre-)Academics 7.8 2.4 10.2 2.9 0.90
Home Living 8.7 2.5 11.2 2.8 0.96
Health and Safety 8.5 2.4 11.8 2.1 1.43
Leisure 7.2 2.4 10.5 3.0 1.25
Self-Care 9.5 2.4 10.6 3.0 0.41
Self-Direction 6.9 2.8 11.1 2.2 1.71
Social 6.9 2.3 9.8 2.0 1.37
Adaptive domain
Conceptual 83.7 13.5 102.7 10.0 1.62
Social 84.9 11.5 101.9 11.1 1.51
Practical 92.9 11.3 105.2 11.7 1.06
GAC 82.7 14.8 103.2 10.5 1.62
Note. n = 17. Wilks’ lambda = .376, F(13, 20) = 2.55, p = .029. The Motor and Work adaptive skill areas are 
excluded from this table because they do not appear on both forms.
Table 5.54. Mean ABAS-3 Scaled and Composite Scores, Combined ADHD 
Samples and Matched Control Groups: Teacher/Daycare Provider 
Form (Ages 2–5) and Teacher Form (Ages 5–21)
Children with ADHD Matched control group
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d
Adaptive skill area
Communication 6.3 2.3 9.7 2.8 1.31
aCommunity Use 7.9 2.3 11.2 3.9 1.05
Functional (Pre-)Academics 7.1 2.9 10.6 2.6 1.25
School Living 6.1 2.2 10.0 2.9 1.54
Health and Safety 8.2 2.5 9.8 2.6 0.65
Leisure 7.0 2.6 9.7 2.6 1.02
Self-Care 9.1 2.3 10.7 2.2 0.72
Self-Direction 5.4 2.5 9.7 3.1 1.53
Social 6.9 3.0 9.5 2.8 0.90
Adaptive domain
Conceptual 77.5 11.8 99.4 16.2 1.57
Social 84.7 13.0 99.3 14.9 1.05
Practical 85.1 8.7 102.2 15.9 1.39
GAC 80.9 7.6 99.8 16.1 1.61
Note. n = 21. Wilks’ lambda = .286, F(13, 14) = 2.69, p = .039. The Motor and Work adaptive skill areas are 
excluded from this table because they do not appear on both forms.
an = 15 for Community Use.
ABAS-3 125Validity
Adult Clinical Sample
The Adult Form of the ABAS-3 can be used as either 
a self-report or an informant-report (“rated by oth-
ers”) measure. The ABAS-3 clinical research base 
includes a group of 32 adults rated on both self- and 
informant-report forms. The adult sample is a mixed 
clinical group consisting of 14 individuals with 
ASD, 15 with ID, and 3 with ADHD. These adults 
ranged in age from 15 to 71 years, with a mean age 
of 26.2 years (SD = 12.4). The demographic charac-
teristics of this sample were generally equivalent to 
the standardization sample described in Chapter 4, 
with the exception that males (78%) were somewhat 
overrepresented.
The results of the analyses of the adult clinical sam-
ple are shown in Tables 5.55 and 5.56. For the adult 
self-report data, mean GAC for the clinical group was 
70.4 (SD = 20.9), and mean GAC for the matched con-
trol group was 100.1 (SD = 13.0). The mean effect size 
across all adaptive skill area and adaptive domain 
scores was 1.56. For the adult informant-report data, 
mean GAC for the clinical group was 65.3 (SD = 11.9), 
and mean GAC for the matched control group was 
103.8 (SD = 11.1). The mean effect size across all 
adaptive skill area and adaptive domain scores was 
2.63. These large and clinically meaningful effect 
sizes are consistent with the findings in the child 
and adolescent clinical samples, across diagnostic 
groups and ABAS-3 forms. Taken together, the results 
demonstrate that the ABAS-3 can identify the adap-
tive skill deficits associated with ASD, ID, and ADHD, 
distinguishing children, adolescents, and adults with 
these disorders from their typically functioning peers.
ABAS-II Clinical Group Studies
The following section summarizes clinical group 
comparisons reported in the ABAS-II manual (Harri-
son & Oakland, 2003). Because of the very high level 
of similarity in the item content between ABAS-II and 
ABAS-3, these earlier studies provide validity evi-
dence that is relevant to the ABAS-3.
Children Diagnosed With Developmental Delays
Across two samples, children with developmental 
delays and ranging in age from 8 months to 6 years 
generally yielded significantly lower ABAS-II scores 
than their counterparts in demographically matched 
control groups. An exception to this pattern occurred 
in the sample rated by teachers, in which the develop-
mentally delayed children did not differ significantly 
from the control children in several ABAS-II adaptive 
skill areas. Across both parent and teacher ratings, 
the clinical groups displayed the largest deficit in the 
Communication adaptive skill area.
Children With Known Biological Risk Factors
The ABAS-II manual described two samples of chil-
dren with biological or physical conditions (e.g., low 
birth weight, perinatal respiratory distress, chromo-
somal abnormalities, fetal alcohol syndrome and pre-
natal drug exposure, Down syndrome) and ranging 
in age from newborn to 3 years. Relative to matched 
controls, these children displayed significant deficits 
on ABAS-II GAC and adaptive domains. The high-risk 
children yielded mean GACs of 77 for the Teacher/
Daycare Provider sample and 82 for the Parent/Pri-
mary Caregiver sample. Matched controls had mean 
GACs of 105 and 103 for the Teacher/Daycare Pro-
vider and Parent/Primary Caregiver samples, respec-
tively. Adaptive domains showed deficits of a similar 
magnitude, with the Practical adaptive domain 
displaying the greatest deficit across bothteacher and 
parent ratings.
126 ABAS-3 Chapter 5 Reliability and Validity
Table 5.55. Mean ABAS-3 Scaled and Composite Scores, Mixed Clinical Samples and 
Matched Control Groups: Adult Form (Self-Report) (Ages 16–89)
Mixed clinical sample Matched control group
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d
Adaptive skill area
Communication 5.1 4.0 10.6 2.6 1.66
Community Use 5.1 3.9 10.6 2.5 1.69
Functional Academics 4.9 4.1 10.3 2.5 1.63
Home Living 5.4 3.8 9.8 2.8 1.33
Health and Safety 5.4 3.9 10.3 3.1 1.41
Leisure 4.8 3.9 10.3 2.5 1.71
Self-Care 5.1 4.1 10.1 2.9 1.45
Self-Direction 4.8 3.6 10.2 2.8 1.65
Social 4.9 3.9 10.3 2.7 1.64
Work 6.9 3.6 9.9 3.4 0.85
Adaptive domain
Conceptual 70.5 21.2 100.6 12.7 1.77
Social 72.9 18.9 99.9 12.7 1.71
Practical 72.7 20.0 99.2 12.5 1.64
GAC 70.4 20.9 100.1 13.0 1.75
Note. n = 32. Wilks’ lambda = .411, F(13, 50) = 5.51, ph
e 
st
an
d
ar
d
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co
re
s 
(N
u
n
n
al
ly
 &
 B
er
n
st
ei
n
, 1
9
9
4
).
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ve
ra
ge
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E
M
s 
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er
e 
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lc
u
la
te
d
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y 
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er
ag
in
g 
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m
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u
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E
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s 
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r 
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ch
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ge
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ro
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n
d
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b
ta
in
in
g 
th
e 
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u
ar
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ro
o
t 
of
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h
e 
re
su
lt
.
ABAS-3 71Reliability
Ta
b
le
 5
.4
. I
n
te
rn
al
 C
o
n
si
st
en
cy
 R
el
ia
b
ili
ty
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o
effi
ci
en
ts
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n
d
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E
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s 
of
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ve
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ki
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o
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ai
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h
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A
C
: 
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ta
n
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iz
at
io
n
 S
am
p
le
 b
y 
A
ge
 G
ro
u
p
: T
ea
ch
er
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o
rm
 (
A
ge
s 
5
–
2
1)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/
 
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o
m
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te
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ge
 g
ro
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p
 (
in
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ea
rs
)
5
 
(n
 =
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0
)
6
 
(n
 =
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8
6
)
7 
(n
 =
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73
)
8
 
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5
9
)
9
 
(n
 =
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6
1)
10
 
(n
 =
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6
6
)
11
 
(n
 =
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5
5
)
12
 
(n
 =
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3
8
)
13
–
14
 
(n
 =
 2
0
0
)
15
–
16
 
(n
 =
 1
9
9
)
17
–
2
1 
(n
 =
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3
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)
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W
o
rk
—
—
—
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—
—
—
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0
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2
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2
P
ra
ct
ic
al
 (
w
it
h
o
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W
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rk
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0
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0
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2
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1.
76
0
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7
2
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4
G
A
C
 (
w
it
h
o
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t 
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rk
)
0
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77
0
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9
1.
8
3
0
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57
0
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8
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1
0
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8
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6
2
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8
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8
4
0
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9
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2
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9
1.
77
N
ot
e.
 A
ve
ra
ge
 r
el
ia
b
ili
ty
 c
o
effi
ci
en
ts
 (
r x
x
) 
w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
Fi
sh
er
’s
 z
 t
ra
n
sf
o
rm
at
io
n
. A
d
ap
ti
ve
 d
o
m
ai
n
 a
n
d
 G
A
C
 r
el
ia
b
ili
ti
es
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
th
e 
fo
rm
u
la
 fo
r 
re
lia
b
ili
ty
 o
f l
in
ea
r 
co
m
b
in
at
io
n
s 
u
si
n
g 
th
e 
su
m
 o
f t
h
e 
st
an
d
ar
d
 s
co
re
s 
(N
u
n
n
al
ly
 &
 B
er
n
st
ei
n
, 1
9
9
4
).
 A
ve
ra
ge
 S
E
M
s 
w
er
e 
ca
lc
u
la
te
d
 b
y 
av
er
ag
in
g 
th
e 
su
m
 o
f t
h
e 
sq
u
ar
ed
 S
E
M
s 
fo
r 
ea
ch
 a
ge
 g
ro
u
p
 a
n
d
 o
b
ta
in
in
g 
th
e 
sq
u
ar
e 
ro
o
t 
of
 t
h
e 
re
su
lt
.
72 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.5
. I
n
te
rn
al
 C
o
n
si
st
en
cy
 R
el
ia
b
ili
ty
 C
o
effi
ci
en
ts
 a
n
d
 S
E
M
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
as
, A
d
ap
ti
ve
 D
o
m
ai
n
s,
 a
n
d
 t
h
e 
G
A
C
: 
S
ta
n
d
ar
d
iz
at
io
n
 S
am
p
le
 b
y 
A
ge
 G
ro
u
p
: A
d
u
lt
 F
o
rm
 (
S
el
f-
R
ep
o
rt
) 
(A
ge
s 
16
–
8
9
)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
A
ge
 g
ro
u
p
 (
in
 y
ea
rs
)
16
–
2
1 
(n
 =
 1
5
2
)
2
2
–
2
9
 
(n
 =
 1
6
5
)
3
0
–
3
9
 
(n
 =
 2
11
)
4
0
–
4
9
 
(n
 =
 1
6
6
)
5
0
–
6
4
 
(n
 =
 1
8
1)
6
5
–
74
 
(n
 =
 7
9
)
75
–
8
9
 
(n
 =
 6
0
)
A
ve
ra
ge
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r x
x
S
E
M
A
d
ap
ti
ve
 s
ki
ll 
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ea
C
o
m
m
u
n
ic
at
io
n
0
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2
0
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4
0
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1
0
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9
0
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3
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U
se
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re
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3
0
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2
0
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4
0
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5
0
.9
4
0
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4
0
.9
6
0
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9
0
.9
2
0
.8
4
0
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6
0
.6
1
0
.9
4
0
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6
S
el
f-
C
ar
e
0
.9
3
0
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9
0
.9
1
0
.9
2
0
.9
0
0
.9
6
0
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2
0
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6
0
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7
0
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8
0
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0
1.
3
3
0
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8
0
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7
0
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3
0
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7
S
el
f-
D
ir
ec
ti
o
n
0
.9
5
0
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0
0
.9
2
0
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5
0
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3
0
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7
0
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5
0
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8
0
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8
0
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7
0
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3
0
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2
0
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3
0
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0
0
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5
0
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4
S
o
ci
al
0
.9
5
0
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5
0
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6
0
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3
0
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3
0
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7
0
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3
0
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9
0
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6
0
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9
0
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0
0
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5
0
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2
0
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4
0
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4
0
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6
W
o
rk
0
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9
0
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0
0
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9
0
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0
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9
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1
0
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9
0
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7
0
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9
0
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6
0
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9
0
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2
—
—
0
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9
0
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8
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
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6
2
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9
0
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6
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8
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0
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5
3.
3
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0
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6
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0
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o
ci
al
0
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6
3.
0
2
0
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7
2
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8
0
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6
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6
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0
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8
2
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3
0
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4
3.
5
3
0
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6
2
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6
0
.9
6
2
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1
P
ra
ct
ic
al
 (
w
it
h
o
u
t 
W
o
rk
)
0
.9
7
2
.7
5
0
.9
7
2
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9
0
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7
2
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2
0
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8
2
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4
0
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9
1.
6
2
0
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5
3.
4
7
0
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8
2
.1
0
0
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8
2
.53
P
ra
ct
ic
al
 (
w
it
h
 W
o
rk
)
0
.9
7
2
.4
1
0
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8
2
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8
0
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8
2
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1
0
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8
1.
9
5
0
.9
9
1.
3
9
0
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6
2
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3
—
—
0
.9
8
2
.2
4
G
A
C
 (
w
it
h
o
u
t 
W
o
rk
)
0
.9
9
1.
8
0
0
.9
9
1.
71
0
.9
9
1.
6
6
0
.9
9
1.
5
3
0
.9
9
1.
10
0
.9
8
2
.2
0
0
.9
9
1.
5
8
0
.9
9
1.
6
8
G
A
C
 (
w
it
h
 W
o
rk
)
0
.9
9
1.
70
0
.9
9
1.
6
2
0
.9
9
1.
5
6
0
.9
9
1.
4
4
0
.9
9
1.
0
3
0
.9
8
2
.0
5
—
—
0
.9
9
1.
6
0
N
ot
e.
 A
ve
ra
ge
 r
el
ia
b
ili
ty
 c
o
effi
ci
en
ts
 (
r x
x
) 
w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
Fi
sh
er
’s
 z
 t
ra
n
sf
o
rm
at
io
n
. A
d
ap
ti
ve
 d
o
m
ai
n
 a
n
d
 G
A
C
 r
el
ia
b
ili
ti
es
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
th
e 
fo
rm
u
la
 fo
r 
re
lia
b
ili
ty
 o
f l
in
ea
r 
co
m
b
in
at
io
n
s 
u
si
n
g 
th
e 
su
m
 o
f t
h
e 
st
an
d
ar
d
 s
co
re
s 
(N
u
n
n
al
ly
 &
 B
er
n
st
ei
n
, 1
9
9
4
).
 A
ve
ra
ge
 S
E
M
s 
w
er
e 
ca
lc
u
la
te
d
 b
y 
av
er
ag
in
g 
th
e 
su
m
 o
f t
h
e 
sq
u
ar
ed
 S
E
M
s 
fo
r 
ea
ch
 a
ge
 g
ro
u
p
 a
n
d
 o
b
ta
in
in
g 
th
e 
sq
u
ar
e 
ro
o
t 
of
 t
h
e 
re
su
lt
.
ABAS-3 73Reliability
Ta
b
le
 5
.6
. I
n
te
rn
al
 C
o
n
si
st
en
cy
 R
el
ia
b
ili
ty
 C
o
effi
ci
en
ts
 a
n
d
 S
E
M
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
as
, A
d
ap
ti
ve
 D
o
m
ai
n
s,
 a
n
d
 t
h
e 
G
A
C
: 
S
ta
n
d
ar
d
iz
at
io
n
 S
am
p
le
 b
y 
A
ge
 G
ro
u
p
: A
d
u
lt
 F
o
rm
 (
R
at
ed
 b
y 
O
th
er
s)
 (
A
ge
s 
16
–
8
9
)
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
A
ge
 g
ro
u
p
 (
in
 y
ea
rs
)
16
–
2
1 
(n
 =
 1
5
0
)
2
2
–
2
9
 
(n
 =
 1
6
7)
3
0
–
3
9
 
(n
 =
 1
9
4
)
4
0
–
4
9
 
(n
 =
 1
5
1)
5
0
–
6
4
 
(n
 =
 1
6
5
)
6
5
–
74
 
(n
 =
 9
8
)
75
–
8
9
 
(n
 =
 7
6
)
A
ve
ra
ge
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r x
x
S
E
M
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
0
.9
5
0
.6
5
0
.9
2
0
.8
5
0
.9
2
0
.8
6
0
.9
1
0
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9
0
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3
0
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1
0
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4
0
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1
0
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9
0
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1
0
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5
0
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5
C
o
m
m
u
n
it
y 
U
se
0
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3
0
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7
0
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2
0
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5
0
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2
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0
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8
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2
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4
0
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9
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0
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4
0
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9
Fu
n
ct
io
n
al
 A
ca
d
em
ic
s
0
.9
2
0
.8
2
0
.8
9
0
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8
0
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0
0
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0
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0
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3
0
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0
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5
0
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7
0
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9
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0
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o
m
e 
Li
vi
n
g
0
.9
3
0
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8
0
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2
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ea
lt
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n
d
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af
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13
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9
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2
Le
is
u
re
0
.9
5
0
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8
0
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3
0
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0
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4
0
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0
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0
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0
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5
0
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5
0
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9
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7
0
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5
0
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8
S
el
f-
C
ar
e
0
.9
6
0
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3
0
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8
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0
6
0
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2
1.
2
8
0
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7
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0
8
0
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9
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0
1
0
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9
0
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8
0
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9
0
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0
0
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2
0
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6
S
el
f-
D
ir
ec
ti
o
n
0
.9
6
0
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6
0
.9
3
0
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8
0
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5
0
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6
0
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5
0
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9
0
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5
0
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0
0
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5
0
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7
0
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9
0
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3
0
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6
0
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4
S
o
ci
al
0
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7
0
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2
0
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4
0
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1
0
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2
0
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3
0
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4
0
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3
0
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3
0
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1
0
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4
0
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3
0
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9
0
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7
0
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6
0
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8
W
o
rk
0
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9
0
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1
0
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7
0
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9
0
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8
0
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8
0
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8
0
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8
0
.9
9
0
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2
0
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9
0
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3
—
—
0
.9
9
0
.3
6
A
d
ap
ti
ve
 d
o
m
ai
n
C
o
n
ce
p
tu
al
0
.9
8
2
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1
0
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6
2
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0
0
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7
2
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9
0
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6
2
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2
0
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7
2
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3
0
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8
2
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5
0
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9
0
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6
0
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8
2
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4
S
o
ci
al
0
.9
8
2
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5
0
.9
6
2
.9
4
0
.9
6
2
.9
7
0
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7
2
.7
2
0
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6
2
.9
0
0
.9
7
2
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6
0
.9
9
1.
2
0
0
.9
7
2
.6
0
P
ra
ct
ic
al
 (
w
it
h
 W
o
rk
)
0
.9
8
1.
8
7
0
.9
7
2
.5
0
0
.9
7
2
.5
4
0
.9
8
2
.2
4
0
.9
7
2
.5
3
0
.9
8
2
.2
0
—
—
0
.9
8
2
.3
3
P
ra
ct
ic
al
 (
w
it
h
o
u
t 
W
o
rk
)
0
.9
8
2
.2
7
0
.9
6
2
.8
7
0
.9
6
3.
0
2
0
.9
7
2
.6
1
0
.9
6
2
.9
7
0
.9
7
2
.6
8
0
.9
9
0
.8
4
0
.9
7
2
.5
6
G
A
C
 (
w
it
h
o
u
t 
W
o
rk
)
0
.9
9
1.
4
5
0
.9
9
1.
8
4
0
.9
9
1.
8
3
0
.9
9
1.
6
8
0
.9
9
1.
79
0
.9
9
1.
6
2
0
.9
9
0
.5
7
0
.9
9
1.
6
0
G
A
C
 (
w
it
h
 W
o
rk
)
0
.9
9
1.
3
2
0
.9
9
1.
72
0
.9
9
1.
6
9
0
.9
9
1.
57
0
.9
9
1.
6
5
0
.9
9
1.
4
6
—
—
0
.9
9
1.
5
8
N
ot
e.
 A
ve
ra
ge
 r
el
ia
b
ili
ty
 c
o
effi
ci
en
ts
 (
r x
x
) 
w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
Fi
sh
er
’s
 z
 t
ra
n
sf
o
rm
at
io
n
. A
d
ap
ti
ve
 d
o
m
ai
n
 a
n
d
 G
A
C
 r
el
ia
b
ili
ti
es
 w
er
e 
ca
lc
u
la
te
d
 u
si
n
g 
th
e 
fo
rm
u
la
 fo
r 
re
lia
b
ili
ty
 o
f l
in
ea
r 
co
m
b
in
at
io
n
s 
u
si
n
g 
th
e 
su
m
 o
f t
h
e 
st
an
d
ar
d
 s
co
re
s 
(N
u
n
n
al
ly
 &
 B
er
n
st
ei
n
, 1
9
9
4
).
 A
ve
ra
ge
 S
E
M
s 
w
er
e 
ca
lc
u
la
te
d
 b
y 
av
er
ag
in
g 
th
e 
su
m
 o
f t
h
e 
sq
u
ar
ed
 S
E
M
s 
fo
r 
ea
ch
 a
ge
 g
ro
u
p
 a
n
d
 o
b
ta
in
in
g 
th
e 
sq
u
ar
e 
ro
o
t 
of
 t
h
e 
re
su
lt
.
74 ABAS-3 Chapter 5 Reliability and Validity
Ta
b
le
 5
.7
. I
n
te
rn
al
 C
o
n
si
st
en
cy
 R
el
ia
b
ili
ty
 C
o
effi
ci
en
ts
 a
n
d
 S
E
M
s 
of
 A
d
ap
ti
ve
 S
ki
ll 
A
re
as
, A
d
ap
ti
ve
 D
o
m
ai
n
s,
 a
n
d
 t
h
e 
G
A
C
: 
M
ix
ed
 C
lin
ic
al
 S
am
p
le
 b
y 
Fo
rm
 T
yp
e
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
/C
o
m
p
o
si
te
Fo
rm
 t
yp
e
P
ar
en
t/
P
ri
m
ar
y 
C
ar
eg
iv
er
a 
(n
 =
 7
5
) 
 
 
 
 
 
Te
ac
h
er
/
D
ay
ca
re
 P
ro
vi
d
er
b
 
(n
 =
 6
8
) 
P
ar
en
tc 
(n
 =
 7
7)
 
Te
ac
h
er
d
 
(n
 =
 7
9
) 
A
d
u
lt
, S
el
f-
R
ep
o
rt
e 
(n
 =
 3
2
) 
A
d
u
lt
, R
at
ed
 b
y 
O
th
er
se 
(n
 =
 3
2
) 
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
r
S
E
M
A
d
ap
ti
ve
 s
ki
ll 
ar
ea
C
o
m
m
u
n
ic
at
io
n
0
.9
7
0
.4
9
0
.9
8
0
.4
5
0
.9
5
0
.7
0
0
.9
4
0
.7
2
0
.9
7
0
.5
4
0
.9
6
0
.6
0
C
o
m
m
u
n
it
y 
U
se
0
.9
6
0
.5
7
—
—
0
.9
6
0
.5
7
0
.9
3
0
.8
0
0
.9
7
0
.4
8
0
.9
7
0
.4
9
Fu
n
ct
io
n
al
 A
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ABAS-3 75Reliability
Overall, the reliability data suggest that the scaled 
scores of adaptive skill areas, as well as the standard 
scores of adaptive domains and GAC, reflect a high 
degree of internal consistency in the items. Further, 
the ABAS-3 scores retain this level of internal consis-
tency in groups of individuals with different clinical 
diagnoses.
Standard Errors of Measurement and 
Confidence Intervals 
The standard error of measurement statistic (SEM) 
translates a reliability estimate into more practical 
terms by providing an index of how close an individ-
ual’s observed score is to their “true” score (i.e., what 
the score would be if there were no measurement 
error). The SEM is inversely related to the reliability 
of the scale. Therefore, greater reliability means a 
smaller SEM, which increases the amount of confi-
dence the clinician can have in the precision of the 
observed test score.
The SEM is calculated using the formula SEM = 
SD √1−rx, where SD is the standard deviation of the 
scale and rx is the reliability coefficient of the scale. 
Comparisons should not be made between the SEMs 
of the adaptive skill area scaled scores and the GAC 
or adaptive domain standard scores because they are 
based on different standard deviation units (adaptive 
skill area scores have an SD of 3; adaptive domain 
standard scores and the GAC have an SD of 15).
The SEMs for the adaptive skill area, adaptive 
domain, and GAC scores are shown next to the reli-
ability coefficients in Tables 5.1 through 5.6 for each 
of the standardization samples, corresponding to 
each of the ABAS-3 forms, and in Table 5.7 for indi-
viduals with various clinical diagnoses. As demon-
strated by the internal consistency data, the ABAS-3 
reliability coefficients range from good to excellent 
for both the standardization samples and for assess-
ing individuals with different clinical diagnoses.
The SEM can be converted into a confidence interval 
(CI) that gives a range of probable values for the true 
score. For example, the 95% CI represents the range 
of scores around the observed score that has a 95% 
probability of containing the true score. The confi-
dence values at 90% and 95% are provided in the 
normative tables in Appendix A and are expressed 
in standard score units, rounded to the nearest whole 
number. These confidence values were derived from 
the internal consistency estimates and SEM values 
of the standardization sample. Chapter 3 describes 
the procedure for using confidence intervals in score 
interpretation.
Test–Retest Reliability
Test–retest reliability, also known as temporal sta-
bility, refers to the stability of test scores over time. 
Test–retest reliability is estimated by having a single 
respondent rate the individual, using the same form, 
on two separate occasions (Time 1 and Time 2), and 
correlating the resulting scores. The ABAS-3 mean 
test–retest interval was 3 weeks, with time intervals 
ranging from 5 days to 7 weeks. Over intervals of 
such brief durations, test scores are not expected to 
change appreciably due to development of the under-
lying abilities. However, scores may change as a result 
of random variations in ratings of behavior.
The ABAS-3 retest studies include a total of 265 chil-
dren and adults from the standardization sample, 
with some cases rated across multiple ABAS-3 form 
types. In this sample, children ranged in age from 
0 to 18 years (M = 4.6 years, SD = 4.7) and adults 
ranged from 16 to 84 years (M = 41.5 years, SD = 17.8). 
The combined retest sample was 45% male and 55% 
female with 61.3% White, 18.1% Black, 9.1% Hispanic, 
and 11.5% other ethnicities. In terms of head-of-
household education level, 44.7% of the sample had 
a 4-year college degree or higher, and 21.9% had a 
high-school degree or less. The retest clinical sample 
included 60 children and adults with a diagnosis of 
autism spectrum disorder (ASD), with some cases 
rated across multiple ABAS-3 form types (Teacher/
Daycare Provider, n = 42; Teacher, n = 7; Parent/Pri-
mary Caregiver, n = 39; Parent, n = 7; Adult self-report, 
n = 10; Adult rated by others, n = 11). In the clinical 
sample, children ranged in age from 2 to 20 years 
(M = 5.2 years, SD = 3.6) and adults ranged from 
17 to 71 years (M = 31.6 years, SD = 15.7). Com-
parison of scaled and standard scores allowed the 
inclusion of all ABAS-3 forms in the same analysis. 
The mixed clinical sample was 75% male and 25% 
female with 69.4% White, 8.2% Black, 8.2% Hispanic, 
and 14.4% other ethnicities. In terms of head-of-
household education level, 43.1% of the sample had 
a 4-year college degree or higher, and 13.8% had a 
high-school degree or less.
76 ABAS-3 Chapter 5 Reliability and Validity
Two analyses were conducted on the test–retest data: 
the effect size of the difference in scores between 
Time 1 and Time 2 using scaled scores for adaptive 
skill areas, standard scores for the adaptive domains 
and the GAC, and corrected Pearson correlation 
coefficients.1 The test–retest results are presented in 
Tables 5.8 through 5.13 for the standardization sam-
ple only as it is representative of the clinical sample, 
which displayed the same pattern of results.
Table 5.8 presents the Parent/Primary Caregiver 
Form retest results for 151 children, ages 0 to 5 years. 
The average effect size of the difference between 
Time 1 and Time 2 was .01 for the adaptive skill area 
scaled scores, .01 for the adaptive domain standard 
scores, and .01 for the GAC score. The average cor-
rected test–retest correlation was .70 for the adaptive 
skill area scaled scores, .76 for the adaptive domain 
standard scores, and .82 for the GAC score, indicat-
ing an increasing degree of correspondence from the 
adaptive skill areas through the adaptive domains to 
the GAC.
Table 5.9 presents the Parent Form results for 77 chil-
dren, ages 5 to 21 years. The average effect size of the 
difference between Time 1 and Time 2 was .04 for the 
adaptive skill area scaled scores, .06 for the adaptive 
domain standard scores, and .02 for the GAC score. The 
average corrected test–retest correlation was .77 for the 
adaptive skill area scaled scores, .80 for the adaptive 
domain standard scores, and .86 for the GAC score.
Table 5.10 presents the Teacher/Daycare Provider 
Form results for 39 children, ages 2 to 5 years. The 
average effect size of the difference between Time 1 
and Time 2 was .10 for the adaptive skill area scaled 
scores, .11 for the adaptive domain standard scores, 
and .12 for the GAC score. The average corrected test–
retest correlation was .80 for the adaptive skill area 
scaled scores, .80 for the adaptive domain standard 
scores, and .86 for the GAC score.
Table 5.11 presentsthe Teacher Form results for 
77 children, ages 5 to 21 years. The average effect size 
of the difference between Time 1 and Time 2 was 
.07 for the adaptive skill area scaled scores, .03 for the 
adaptive domain standard scores, and .03 for the GAC 
score. The average corrected test–retest correlation 
was .80 for the adaptive skill area scaled scores, .81 for 
the adaptive domain standard scores, and .84 for the 
GAC score.
Table 5.12 presents the Adult Form results for 36 adults, 
ages 16 to 84 years, who completed a self-report. The 
average effect size of the difference between Time 1 
and Time 2 was .22 for the adaptive skill area scaled 
scores, .26 for the adaptive domain standard scores, 
and .28 for the GAC score. The average corrected test–
retest correlation was .76 for the adaptive skill area 
scaled scores, .85 for the adaptive domain standard 
scores, and .87 for the GAC score.
Table 5.13 presents the Adult Form results for 37 adults, 
ages 16 to 84 years, who were rated by another 
respondent (spouse, sibling, caregiver, and so forth). 
The average effect size of the difference between Time 
1 and Time 2 was .08 for the adaptive skill area scaled 
scores, .07 for the adaptive domain standard scores, 
and .05 for the GAC score. The average corrected test–
retest correlation was .75 for the adaptive skill area 
scaled scores, .85 for the adaptive domain standard 
scores, and .89 for the GAC score.
For the ABAS-3 standardization and clinical samples, 
comparison of Time 1 and Time 2 scores produce 
overall small effect sizes with moderate to strong cor-
rected correlations. This indicates negligible change 
from Time 1 to Time 2 in the scaled scores of the 
adaptive skill areas and standard scores of the adap-
tive domains and GAC.
These results show that the test–retest reliability of 
ABAS-3 scores is acceptable for clinical use and con-
sistent with that of other behavior rating scales.
1 In this manual, effect sizes report standardized differences between group means. An effect size metric (Cohen’s d) can help gauge 
whether group differences are large enough to be considered clinically meaningful. An effect size of 0.2 is considered small; of 0.5, 
medium; and of 0.8, large (Cohen, 1992). The absolute value of the effect size indicates its magnitude, whereas the sign (+/−) indicates 
the direction of the effect. By convention, a clinically meaningful effect size is at least medium (0.5) in magnitude.
ABAS-3 77Reliability
Table 5.8. Test–Retest Reliability: Parent/Primary Caregiver Form (Ages 0–5)
Time 1 Time 2
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected ra
Adaptive skill area
Communication 9.55 3.35 9.69 3.43 0.03 0.75 0.71
Community Use 8.55 3.12 8.41 3.05 0.03 0.73 0.71
Functional Pre-Academics 9.06 3.68 9.13 3.83 0.01 0.75 0.67
Home Living 7.94 4.27 7.95 4.33 0.00 0.74 0.62
Health and Safety 9.57 2.98 9.58 2.99 0.00 0.72 0.73
Leisure 8.94 3.95 8.79 4.23 0.02 0.72 0.62
Self-Care 9.53 3.36 9.64 3.55 0.02 0.79 0.76
Self-Direction 8.96 3.46 8.94 3.47 0.00 0.80 0.75
Social 9.05 3.66 9.12 3.68 0.01 0.76 0.69
Motor 9.99 3.23 10.08 3.45 0.02 0.78 0.75
Adaptive domain
Conceptual 95.19 15.64 95.51 16.42 0.01 0.78 0.77
Social 93.72 17.87 93.24 18.40 0.02 0.72 0.66
Practical 94.93 15.07 94.74 15.67 0.01 0.84 0.84
GAC 93.98 15.33 94.11 16.37 0.01 0.83 0.82
Note. n = 151; n with CU, FA, and HL = 112.
aCorrelation coefficients are corrected for variability of Time 1 (scaled score SD = 3, standard score SD = 15) using Guilford’s (1954) 
formula.
Table 5.9. Test–Retest Reliability: Parent Form (Ages 5–21)
Time 1 Time 2
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected ra
Adaptive skill area
Communication 11.01 2.70 10.60 2.72 0.10 0.75 0.78
Community Use 11.13 2.98 10.90 3.16 0.05 0.73 0.73
Functional Academics 11.23 2.92 11.10 3.12 0.03 0.75 0.75
Home Living 10.48 3.02 10.61 2.97 0.03 0.74 0.74
Health and Safety 10.49 2.83 10.39 2.88 0.02 0.72 0.74
Leisure 11.23 2.54 11.30 2.76 0.02 0.72 0.77
Self-Care 10.51 2.71 10.75 3.17 0.06 0.79 0.82
Self-Direction 10.77 2.79 10.97 3.02 0.05 0.80 0.82
Social 10.82 2.56 10.86 2.56 0.01 0.76 0.81
Adaptive domain
Conceptual 105.56 13.62 104.70 14.19 0.04 0.78 0.81
Social 105.87 14.56 105.96 13.34 0.14 0.72 0.73
Practical 103.00 14.02 103.12 14.55 0.01 0.84 0.85
GAC 104.75 12.92 104.39 14.10 0.02 0.83 0.86
Note. n = 77.
aCorrelation coefficients are corrected for variability of Time 1 (scaled score SD = 3, standard score SD = 15) using Guilford’s (1954) 
formula.
78 ABAS-3 Chapter 5 Reliability and Validity
Table 5.10. Test–Retest Reliability: Teacher/Daycare Provider Form (Ages 2–5)
Time 1 Time 2
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected ra
Adaptive skill area
Communication 10. 31 2.42 10.85 1.87 0.16 0.75 0.81
Functional Pre-Academics 11.05 2.74 11.44 2.90 0.09 0.75 0.78
School Living 9.64 2.64 10.05 2.50 0.11 0.74 0.78
Health and Safety 9.60 2.31 10.28 2.04 0.20 0.72 0.81
Leisure 10.05 2.55 10.38 2.09 0.09 0.72 0.77
Self-Care 10.62 2.55 11.03 2.72 0.10 0.79 0.84
Self-Direction 10.31 2.73 10.31 2.47 0.00 0.80 0.82
Social 10.00 2.65 10.51 2.45 0.13 0.76 0.80
Motor 10.67 2.71 10.72 2.91 0.01 0.78 0.81
Adaptive domain
Conceptual 102.23 13.67 103.41 11.99 0.06 0.78 0.81
Social 100.28 14.19 102.64 12.63 0.12 0.72 0.74
Practical 98.44 14.01 101.54 13.63 0.15 0.84 0.85
GAC 99.46 13.00 101.82 12.35 0.12 0.83 0.86
Note. n = 39.
aCorrelation coefficients are corrected for variability of Time 1 (scaled score SD = 3, standard score SD = 15) using Guilford’s (1954) 
formula.
Table 5.11. Test–Retest Reliability: Teacher Form (Ages 5–21)
Time 1 Time 2
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected ra
Adaptive skill area
Communication 10.56 2.60 10.27 2.82 0.07 0.75 0.79
Community Use 11.04 2.91 10.82 3.14 0.05 0.73 0.74
Functional Academics 10.44 2.97 10.08 3.23 0.08 0.75 0.75
School Living 10.26 2.41 10.14 2.60 0.03 0.74 0.81
Health and Safety 10.70 2.59 10.00 2.68 0.18 0.72 0.77
Leisure 10.48 2.23 10.35 2.65 0.04 0.72 0.81
Self-Care 10.23 2.50 10.37 2.74 0.04 0.79 0.84
Self-Direction 10.36 2.71 10.25 2.82 0.03 0.80 0.83
Social 10.16 2.38 10.50 2.53 0.09 0.76 0.83
Adaptive domain
Conceptual 102.81 14.42 101.99 15.75 0.04 0.78 0.79
Social 102.86 12.73 102.99 13.15 0.01 0.72 0.78
Practical 103.77 14.00 102.74 15.21 0.05 0.84 0.85
GAC 103.44 14.29 102.79 15.52 0.03 0.83 0.84
Note. n = 77.
aCorrelation coefficients are corrected for variability of Time 1 (scaled score SD = 3, standard score SD = 15) using Guilford’s (1954) 
formula.
ABAS-3 79Reliability
Table 5.12. Test–Retest Reliability: Adult Form (Self-Report) (Ages 16–89)
Time 1 Time 2
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected ra
Adaptive skill area
Communication 11.35 2.68 11.97 2.25 0.16 0.75 0.78
Community Use 10.76 2.87 11.44 2.80 0.16 0.73 0.74
Functional Academics 11.03 2.96 11.81 2.58 0.18 0.75 0.75
Home Living 10.74 3.93 11.89 3.02 0.21 0.74 0.65
Health and Safety 11.41 3.20 12.42 2.76 0.22 0.72 0.70
Leisure 10.18 2.58 11.19 2.16 0.28 0.72 0.77
Self-Care 11.68 2.06 12.42 1.84 0.25 0.79 0.88
Self-Direction 10.94 2.67 11.94 2.19 0.27 0.80 0.83
Social 11.64 2.01 12.11 1.56 0.17 0.76 0.87
Work 10.23 4.18 11.72 2.85 0.27 0.78 0.66
Adaptive domain
Conceptual 104.41 13.15 109.03 11.38 0.25 0.78 0.82
Social 102.56 10.18 106.61 9.25 0.27 0.72 0.84
Practical (without Work) 102.27 12.46 106.67 10.44 0.25 0.79 0.84
Practical (with Work) 103.77 11.62 108.03 9.30 0.26 0.84 0.89
GAC (without Work) 103.44 12.56 109.06 11.36 0.31 0.83 0.87
GAC (with Work) 104.33 12.47 108.97 10.78 0.26 0.83 0.87
Note. n = 36; n with Work = 29.
aCorrelation coefficients are corrected for variability of Time 1 (scaled score SD = 3, standard score SD = 15) using Guilford’s (1954) 
formula.
Table 5.13. Test–Retest Reliability: Adult Form (Rated by Others) (Ages 16–89)
Time 1 Time 2
Adaptive skill area/CompositeMean SD Mean SD Effect size r Corrected ra
Adaptive skill area
Communication 12.37 2.78 12.68 2.21 0.08 0.75 0.77
Community Use 11.66 2.91 12.03 2.36 0.09 0.73 0.74
Functional Academics 11.63 2.92 11.89 2.49 0.06 0.75 0.75
Home Living 11.09 3.04 11.35 2.63 0.06 0.74 0.74
Health and Safety 12.00 3.31 12.16 2.47 0.04 0.72 0.69
Leisure 10.49 2.76 10.92 2.67 0.11 0.72 0.75
Self-Care 12.34 2.42 12.35 2.25 0.00 0.79 0.85
Self-Direction 11.03 3.02 11.62 2.94 0.13 0.80 0.80
Social 11.54 2.37 11.81 2.12 0.08 0.76 0.83
Work 10.55 4.64 11.54 3.04 0.16 0.78 0.63
Adaptive domain
Conceptual 104.86 12.00 106.86 10.44 0.12 0.78 0.84
Social 104.37 12.71 106.11 12.43 0.09 0.72 0.78
Practical (without Work) 105.26 11.57 106.22 10.58 0.06 0.79 0.86
Practical (with Work) 103.90 10.98 104.25 10.65 0.02 0.84 0.90
GAC (without Work) 104.59 11.80 105.97 11.07 0.08 0.83 0.88
GAC (with Work) 105.19 11.49 105.68 11.54 0.03 0.83 0.89
Note. n = 37; n with Work = 28.
aCorrelation coefficients are corrected for variability of Time 1 (scaled score SD = 3, standard score SD = 15) using Guilford’s (1954) 
formula.
80 ABAS-3 Chapter 5 Reliability and Validity
Interrater Reliability
Another method of evaluating the reliability of a 
rating scale is to examine the correlation between 
scores obtained from different respondents (e.g., 
two parents) who rated the same individual using 
the same form. For the ABAS-3, interrater reliability 
was evaluated with a total sample of 459 individu-
als. In this sample, children ranged in age from 0 to 
18 years (M = 4.3 years, SD = 4.2) and adults from 16 
to 89 years (M = 56.0 years, SD = 19.7). The sample 
was 47.4% male and 52.6% female with 70.5% White, 
5.6% Hispanic, 8.2% Asian, 8.6% multiracial, and 
7.1% other ethnicities. The sample tended toward 
higher social economic status (SES), with 70.6% of the 
heads of household having a 4-year college degree or 
higher, and 3.3% a high-school degree or less.
Two analyses were conducted on the interrater data: 
the effect size of the difference scores between the two 
respondents’ adaptive skill area scaled scores, adap-
tive domain standard scores, and GAC score; and 
corrected Pearson correlation coefficients. Results 
are presented separately for each of the five forms in 
Tables 5.14 to 5.18 (note that there is no comparison 
for Adult self-report).
As compared to internal consistency and test–retest 
reliability, interrater reliability is subject to greater 
measurement error due to the two respondents’ dif-
fering experiences with the rated individual. Scores 
from the two respondents are expected to correlate 
moderately with each other, but the correlations are 
not expected to be as strong as the internal con-
sistency or test–retest analyses. Interrater studies 
emphasize the value of obtaining multiple ratings 
of—and therefore different perspectives about—indi-
viduals in clinical settings.
Table 5.14 describes the results from 201 children, 
ages 0–5, who were rated by two respondents on the 
Parent/Primary Caregiver Form. The average effect 
size of the differences between the two respondents’ 
adaptive skill area scaled scores was −.02; for the 
adaptive domain standard scores, −.05; and for the 
GAC score, −.04. These small effect sizes indicate that 
random variation in the magnitude and direction of 
score differences tends to cancel out across the entire 
range of ABAS-3 scores. The average corrected corre-
lation across the adaptive skill area scaled scores was 
.67; for the adaptive domain standard scores, .81; and 
for the GAC score, .85. These all indicate a moderate 
to strong level of correspondence. 
Twenty-six children ages 2–5 were rated by two 
respondents on the Teacher/Daycare Provider Form 
(see Table 5.16). The average effect size for the adap-
tive skill area scaled score comparisons was .07; for 
the adaptive domain standard scores, .14; and for the 
GAC score, .14. The average corrected correlation for 
the adaptive skill area scaled scores was .67; for the 
adaptive domain standard scores, .80; and for the GAC 
score, .92.
Table 5.15 reports 113 children and adolescents, ages 
5–21, who were rated by two respondents on the 
Parent Form. The average effect size for the adaptive 
skill area scaled score comparisons was −.03; for the 
adaptive domain standard scores, −.03; and for the 
GAC score, −.04. The average corrected correlation 
for the adaptive skill area scaled scores was .71; for 
the adaptive domain standard scores, .77; and for the 
GAC score, .83.
Thirty-one children and adolescents, ages 5–21, 
were rated by two teachers on the Teacher Form. As 
presented in Table 5.17, the average effect size for the 
adaptive skill area scaled score comparisons was −.09; 
for the adaptive domain standard scores, −.12; and 
for the GAC score, −.14. The average corrected corre-
lation for the adaptive skill area scaled scores was .72; 
for the adaptive domain standard scores, .78; and for 
the GAC score, .81.
Finally, 88 adults were rated by two informants on 
the ABAS-3 Adult Form. As shown in Table 5.18, the 
average effect size for the adaptive skill area scaled 
score comparisons was .05; for the adaptive domain 
standard scores, −.07; and for the GAC score, .07. The 
average corrected correlation for the adaptive skill 
area scaled scores was .74; for the adaptive domain 
standard scores, .83; and for the GAC score, .87.
These results show that the interrater reliability of 
ABAS-3 scores is acceptable for clinical use and con-
sistent with that of other behavior rating scales.
ABAS-3 81Reliability
Table 5.14. Interrater Reliability: Parent/Primary Caregiver Form (Ages 0–5)
First respondent Second respondent
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.5 3.1 10.4 3.4 –0.01 0.78 0.76
Community Use 9.9 2.8 9.9 2.9 0.00 0.64 0.67
Functional Pre-Academics 10.9 2.6 11.1 2.7 0.06 0.61 0.67
Home Living 10.5 2.5 10.4 2.9 –0.03 0.70 0.76
Health and Safety 10.3 2.7 10.3 2.7 –0.01 0.51 0.56
Leisure 11.3 2.7 10.9 2.9 –0.11 0.57 0.61
Self-Care 10.2 2.5 10.2 2.4 0.00 0.64 0.71
Self-Direction 10.7 2.8 10.5 2.8 –0.05 0.53 0.56
Social 10.7 2.8 10.5 2.7 –0.04 0.63 0.66
Motor 11.0 2.4 11.1 2.3 0.03 0.60 0.68
Adaptive domain
Conceptual 102.5 10.9 102.1 11.2 –0.02 0.71 0.81
Social 103.9 10.3 102.3 10.5 –0.10 0.66 0.79
Practical 101.7 10.2 101.3 10.5 –0.02 0.70 0.82
GAC 102.1 9.6 101.5 10.0 –0.04 0.72 0.85
Note. n = 201; n with CU, FA, and HL = 133.
Table 5.15. Interrater Reliability: Parent Form (Ages 5–21)
First respondent Second respondent
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 11.2 2.2 10.8 2.4 –0.14 0.55 0.67
Community Use 10.7 2.6 10.7 2.7 0.01 0.63 0.68
Functional Academics 11.2 2.6 10.8 2.6 –0.09 0.72 0.77
Home Living 10.0 2.3 9.9 2.3 –0.04 0.63 0.73
Health and Safety 11.2 2.4 11.1 2.3 –0.03 0.53 0.62
Leisure 11.5 2.2 11.8 2.0 0.08 0.52 0.64
Self-Care 11.1 2.3 11.0 2.2 –0.03 0.69 0.78
Self-Direction 10.6 2.6 10.6 2.7 0.00 0.67 0.73
Social 11.0 2.2 10.9 2.3 –0.01 0.63 0.73
Adaptive domain
Conceptual 105.0 10.5 103.4 10.5 –0.10 0.70 0.82
Social 106.4 10.9 107.0 10.3 0.04 0.62 0.74
Practical 103.0 10.6 102.6 10.3 –0.02 0.64 0.76
GAC 104.3 10.1 103.7 9.7 –0.04 0.71 0.83
Note. n = 113.
82 ABAS-3 Chapter 5 Reliability and Validity
Table 5.16. Interrater Reliability: Teacher/Daycare Provider Form (Ages 2–5)
First respondent Second respondent
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.3 2.8 11.2 2.2 0.23 0.52 0.56
Functional Pre-Academics 10.7 2.9 11.5 2.8 0.20 0.73 0.73
School Living 10.0 2.5 10.2 2.6 0.04 0.66 0.72
Health and Safety 9.9 2.3 10.4 2.0 0.14 0.48 0.58
Leisure 10.5 2.6 11.4 2.5 0.23 0.74 0.79
Self-Care 10.4 2.0 10.0 2.2 –0.10 0.46 0.62
Self-Direction 10.3 3.2 10.6 3.0 0.07 0.81 0.80
Social 10.1 2.6 10.7 2.4 0.16 0.59 0.65
Motor 10.91.7 10.0 2.0 –0.31 0.37 0.57
Adaptive domain
Conceptual 99.9 13.0 103.5 12.4 0.19 0.83 0.86
Social 100.5 12.7 104.3 11.5 0.21 0.82 0.86
Practical 99.3 11.8 99.9 11.9 0.03 0.59 0.68
GAC 99.3 11.9 101.8 11.8 0.14 0.88 0.92
Note. n = 26.
Table 5.17. Interrater Reliability: Teacher Form (Ages 5–21)
First respondent Second respondent
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.7 2.2 10.4 2.5 –0.09 0.63 0.74
Community Use 10.7 2.3 10.5 2.6 –0.07 0.68 0.76
Functional Academics 10.7 2.1 10.5 2.1 –0.08 0.69 0.80
School Living 10.9 2.2 10.7 2.2 –0.06 0.48 0.61
Health and Safety 10.7 1.9 10.4 1.9 –0.12 0.54 0.71
Leisure 10.1 2.3 9.9 1.9 –0.06 0.60 0.70
Self-Care 11.3 2.0 11.1 2.3 –0.05 0.56 0.70
Self-Direction 11.5 2.4 10.9 2.7 –0.16 0.70 0.78
Social 10.7 2.1 10.3 2.3 –0.12 0.57 0.70
Adaptive domain
Conceptual 105.2 11.4 102.7 12.3 –0.14 0.69 0.78
Social 102.9 11.7 100.8 10.7 –0.12 0.67 0.76
Practical 104.3 9.3 103.0 10.1 –0.09 0.63 0.79
GAC 104.5 10.9 102.2 11.2 –0.14 0.70 0.81
Note. n = 31.
ABAS-3 83Reliability
Table 5.18. Interrater Reliability: Adult Form (Rated by Others) (Ages 16–89)
First respondent Second respondent
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.6 3.2 10.9 3.3 0.06 0.75 0.72
Community Use 10.3 3.1 10.7 2.9 0.09 0.73 0.71
Functional Academics 10.7 3.3 10.8 3.5 0.02 0.75 0.71
Home Living 10.5 3.0 11.0 2.9 0.11 0.74 0.74
Health and Safety 11.3 3.4 11.5 3.7 0.04 0.72 0.68
Leisure 9.9 3.0 10.3 2.8 0.09 0.72 0.72
Self-Care 10.4 3.2 10.5 3.5 0.02 0.79 0.77
Self-Direction 10.8 3.2 11.1 3.3 0.06 0.80 0.78
Social 10.7 2.6 10.7 2.8 0.00 0.76 0.80
Work 11.7 3.3 11.8 3.2 0.02 0.78 0.75
Adaptive domain
Conceptual 99.9 13.8 101.6 15.0 0.08 0.78 0.81
Social 100.4 12.0 101.4 11.9 0.06 0.72 0.80
Practical (without Work) 99.3 11.3 101.2 12.1 0.11 0.79 0.87
Practical (with Work) 99.2 13.1 100.0 13.3 0.04 0.84 0.87
GAC (without Work) 99.7 12.2 101.4 13.0 0.09 0.83 0.88
GAC (with Work) 99.5 13.6 100.4 13.8 0.04 0.83 0.85
Note. n = 88; n without Work = 49.
84 ABAS-3 Chapter 5 Reliability and Validity
Cross-Form Consistency
Cross-form consistency refers to studies in which two 
respondents rate an individual on two different forms 
(e.g., Parent and Teacher forms). In clinical applica-
tions, ABAS-3 users should strive to obtain multiple 
ratings on the same individual, providing insight into 
the individual’s functioning in different settings and 
as perceived by different respondents. The expecta-
tion is that there will be at most a moderate associa-
tion between the scores provided by different raters 
who use different forms. The cross-form ratings may 
vary, because the two respondents are observing the 
rated individual in varying environments, at differ-
ent times, through different roles, and under variable 
conditions.
Most cases in the ABAS-3 standardization samples 
included two different forms from two different 
respondents: parent and teacher ratings for chil-
dren and adolescents, and self- and other-ratings for 
adults. In their demographic characteristics, the sub-
samples did not differ significantly from the full stan-
dardization samples (see Chapter 4 for demographic 
information for the standardization samples). Two 
analyses were conducted on the cases with pairs of 
forms. The first of these examined the effect size of 
the difference scores between the two forms’ adap-
tive skill area scaled scores, adaptive domain stan-
dard scores, and GAC scores. The second examined 
corrected Pearson correlation coefficients. Results of 
these analyses are presented in Tables 5.19 to 5.21.
Ratings of 545 children ages 2–5 on the Parent/
Primary Caregiver and Teacher/Daycare Provider 
forms were compared. The average effect size for the 
adaptive skill area scaled score differences was −.05; 
for the adaptive domain standard scores, −.05; and 
for the GAC score, −.06. These all indicate small dif-
ferences between mean scores. As expected, the cor-
rected correlations were low to moderate. The average 
corrected correlation for the adaptive skill area scaled 
scores was .41; for the adaptive domain standard 
scores, .47; and for the GAC score, .52.
Ratings of 1,349 individuals ages 5–21 on the Par-
ent and Teacher forms were compared and yielded 
results similar to those for the younger children. The 
average effect size for the adaptive skill area scaled 
score differences was .02; for the adaptive domain 
standard scores, .03; and for the GAC score, .04. The 
average corrected correlation for the scaled scores 
was .46; for the adaptive domain standard scores, .52; 
and for the GAC score, .55. This level of correspon-
dence is consistent with past research, summarized 
by Boan and Harrison (1997), that has found gener-
ally low to moderate correlations between parent 
and teacher scores on adaptive skill instruments and 
supports the inclusion of both parents and teacher in 
a comprehensive assessment of adaptive behavior.
The comparisons between the self-ratings and ratings 
by others of 831 adults ages 16–89 showed a higher 
level of correspondence than those between parents 
and teachers. The average effect size for the adaptive 
skill area scaled score differences was −.05; for the 
adaptive domain standard scores, −.14; and for the 
GAC score, −.17. The average corrected correlation 
for the scaled scores was .64; for the adaptive domain 
standard scores, .74; and for the GAC score, .75. The 
moderate to high correlations presented in Table 
5.21 show considerable consistency when adults rate 
themselves and when others rate them. However, the 
differences between ratings from two respondents 
(i.e., self and others) may, in clinical applications, help 
to characterize the unique strengths and challenges 
of the rated individual.
ABAS-3 85Reliability
Table 5.19. Cross-Form Consistency: Parent/Primary Caregiver Form and 
Teacher/Daycare Provider Form Ratings: Ages 2–5
Parent/Primary 
Caregiver Form
Teacher/Daycare 
Provider Form
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.7 2.6 10.4 2.3 –0.08 0.42 0.47
Functional Pre-Academics 10.6 3.2 10.5 2.9 –0.02 0.49 0.46
Home/School Living 10.6 2.8 10.4 2.5 –0.05 0.38 0.41
Health and Safety 10.4 2.8 10.4 2.4 0.01 0.36 0.38
Leisure 10.9 2.6 10.3 2.4 –0.16 0.31 0.34
Self-Care 10.7 2.9 10.5 2.3 –0.04 0.33 0.34
Self-Direction 10.6 2.8 10.4 2.7 –0.03 0.36 0.39
Social 10.2 2.7 10.4 2.7 0.03 0.33 0.36
Motor 10.8 2.7 10.5 2.9 –0.07 0.47 0.50
Adaptive domain
Conceptual 102.6 12.7 100.7 13.2 –0.10 0.50 0.56
Social 102.0 12.1 101.7 13.3 –0.02 0.32 0.39
Practical 102.0 13.0 101.5 13.3 –0.03 0.40 0.45
GAC 101.8 12.7 100.6 13.2 –0.06 0.46 0.52
Note. n = 545.
Table 5.20. Cross-Form Consistency: Parent Form and Teacher Form Ratings: Ages 5–21
Parent Form Teacher Form
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.1 2.8 10.2 2.7 0.04 0.43 0.46
Community Use 10.1 3.0 10.8 3.1 0.14 0.34 0.34
Functional Academics 10.1 3.1 10.3 2.9 0.04 0.47 0.46
Home/School Living 10.1 3.0 10.1 2.7 –0.01 0.31 0.31
Health and Safety 10.4 2.9 10.0 2.6 –0.08 0.37 0.38
Leisure 10.3 3.0 10.1 2.7 –0.04 0.49 0.48
Self-Care 10.3 2.8 10.2 2.6 –0.02 0.45 0.48
Self-Direction 10.2 3.1 10.1 2.7 –0.01 0.43 0.42
Social 9.9 2.8 9.9 2.6 –0.01 0.51 0.53
Work 9.9 3.7 10.8 2.6 0.18 0.80 0.73
Adaptive domain
Conceptual 100.2 14.3 100.8 14.4 0.02 0.54 0.56
Social 101.0 14.6 101.1 13.9 0.01 0.53 0.54
Practical 100.1 14.1 101.2 14.2 0.06 0.45 0.47
GAC 99.9 14.3 100.8 14.3 0.04 0.54 0.55
Note. n = 1,349; n with Work = 49.
86 ABAS-3 Chapter 5 Reliability and Validity
Table 5.21. Cross-Form Consistency: Adult Form (Self-Report) 
and Adult Form (Rated by Others) Ratings
Adult Form 
(Self-Report)
Adult Form 
(Rated by Others)
Adaptive skill area/CompositeMean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.8 2.6 11.1 3.2 0.06 0.54 0.60
Community Use 10.6 2.6 10.6 3.0 –0.01 0.62 0.68
Functional Academics 10.8 2.5 10.7 3.0 –0.02 0.56 0.63
Home Living 11.1 2.9 10.4 3.0 –0.16 0.61 0.62
Health and Safety 11.5 2.9 11.1 3.3 –0.10 0.61 0.63
Leisure 10.5 2.6 10.3 2.7 –0.05 0.61 0.67
Self-Care 11.1 2.6 10.8 3.2 –0.06 0.56 0.61
Self-Direction 10.8 2.5 10.6 2.9 –0.05 0.60 0.66
Social 10.9 2.5 10.5 2.8 –0.11 0.61 0.67
Work 9.6 4.5 9.5 4.8 –0.02 0.75 0.61
Adaptive domain
Conceptual 102.7 12.2 100.2 13.7 –0.13 0.63 0.70
Social 101.8 11.9 100.6 13.2 –0.07 0.64 0.72
Practical (without Work) 102.2 11.8 99.7 13.3 –0.14 0.68 0.76
Practical (with Work) 102.3 12.2 98.0 13.5 –0.22 0.72 0.78
GAC (without Work) 102.9 12.6 99.7 13.4 –0.16 0.69 0.74
GAC (with Work) 102.6 12.6 99.1 13.3 –0.18 0.70 0.76
Note. n = 831; n with Work = 796.
ABAS-3 87Reliability
Alternate-Forms Reliability
Alternate-forms reliability refers to certain ages 
where two forms overlap, and thus where an indi-
vidual can be rated by the same respondent on 
different forms. On the ABAS-3, alternate-form 
reliability studies were based on three overlapping 
form pairs: the Parent/Primary Caregiver and Par-
ent forms for 5-year-olds, Teacher/Daycare Pro-
vider and Teacher forms for 5-year-olds, and Parent 
and Adult forms for ages 16 to 21. Alternate-forms 
reliability was evaluated with a total sample of 85 
individuals. In this sample, there were 56 5-year-olds 
and 29 adolescents or young adults ages 16 to 21 
(M = 18.4, SD = 1.7). The sample was 50.6% male and 
49.4% female with 60.8% White, 8.6% Hispanic, 10.6% 
Black, 7.1% multiracial, and 12.9% other ethnicities. 
The sample tended toward higher SES, with 70.1% 
of the heads of household having a 4-year college 
degree or higher, and 10.4% a high-school degree or 
less.
Two analyses were conducted on the alternate-forms 
data. The first of these analyzed the effect size of the 
difference scores between the two forms’ adaptive 
skill area scaled scores, adaptive domain standard 
scores, and GAC scores. The second analyzed cor-
rected Pearson correlation coefficients. Results are 
presented for each of the three overlapping form 
pairs in Tables 5.22 to 5.24.
Thirty-seven 5-year-old children were rated by the 
same parent on the Parent/Primary Caregiver and 
Parent forms. Although there is one large effect size 
(.82 for the Social adaptive skill area) and several 
medium effect sizes (e.g., −.37 for the Conceptual 
adaptive domain), the average effect sizes of the dif-
ference between the two forms was near 0, indicating 
that they likely reflect random variations that cancel 
out across all scales and adaptive domains. Further, 
the effect sizes are increased by the restriction of 
range of the scores, yielding larger effect sizes even 
when the mean score differences are small. The aver-
age effect size for the adaptive skill area scaled score 
differences was .05; for the adaptive domain stan-
dard scores, −.11; and for the GAC score, −.12. The 
corrected correlations were moderate to high. The 
average corrected correlation for the adaptive skill 
area scaled scores was .74; for the adaptive domain 
standard scores, .73; and for the GAC score, .79.
Nineteen 5-year-old children were rated by the same 
teacher on the Teacher/Daycare Provider and Teacher 
forms. As with the Parent Form, there were one large 
effect size and several medium effect sizes between 
scores, but the average effect size was near 0, indicat-
ing that the score variation cancels out across scales 
and adaptive domains. Once again, restriction of 
score range tended to inflate effect sizes, even when 
mean differences between scores from the two forms 
were relatively small. The average effect size for the 
adaptive skill area scaled score differences was .06; for 
the adaptive domain standard scores, −.14; and for 
the GAC score, −.17. The corrected correlations were 
moderate to high. The average corrected correlation 
for the adaptive skill area scaled scores was .75; for 
the adaptive domain standard scores, .76; and for the 
GAC score, .84. These two studies suggest that in clini-
cal applications, use of either the “younger” or “older” 
forms (i.e., age 5 and under, and age 5 and older, 
respectively) with 5-year-olds will produce roughly 
equivalent results.
Twenty-nine individuals ages 16 to 21 were rated 
by the same parent on the ABAS-3 Parent and Adult 
forms. There were three medium effect sizes, but 
most were small with a mean near 0, indicating that 
local score variation tends to cancel out across the 
entire group of scales and adaptive domains. The 
average effect size for the adaptive skill area scaled 
score differences was −.12; for the adaptive domain 
standard scores, −.17; and for the GAC score, −.22. 
The corrected correlations were moderate to high. 
The average corrected correlation for the adap-
tive skill area scaled scores was .68; for the adaptive 
domain standard scores, .93; and for the GAC score, 
.95. As with the child forms, the current study sug-
gests that either the Parent Form or Adult Form can 
be used with ages 16 to 21 with equivalent results.
88 ABAS-3 Chapter 5 Reliability and Validity
Table 5.22. Correlations Between the Parent/Primary Caregiver and Parent Forms: Age 5
Parent/Primary 
Caregiver Form Parent Form
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 10.1 1.1 10.8 2.8 0.28 0.42 0.78
Community Use 10.2 2.3 8.8 2.6 –0.40 0.74 0.82
Functional (Pre-)Academics 10.3 1.5 9.6 3.1 –0.22 0.67 0.88
Home Living 10.2 2.6 9.7 2.6 –0.13 0.71 0.76
Health and Safety 10.7 2.5 10.9 2.6 0.06 0.55 0.61
Leisure 11.2 1.7 11.5 2.4 0.13 0.55 0.75
Self-Care 10.3 2.3 10.5 3.4 0.04 0.69 0.78
Self-Direction 10.8 2.4 10.3 2.3 –0.15 0.47 0.56
Social 9.0 1.8 11.5 2.4 0.82 0.54 0.73
Adaptive domain
Conceptual 107.0 9.6 101.4 11.4 –0.37 0.54 0.71
Social 102.6 10.2 106.5 12.0 0.25 0.54 0.69
Practical 102.8 11.9 98.7 14.1 –0.21 0.72 0.79
GAC 103.6 10.5 101.6 12.0 –0.12 0.67 0.79
Note. n = 37.
Table 5.23. Correlations Between the Teacher/Daycare Provider and Teacher Forms: Age 5
Teacher/Daycare 
Provider Form Teacher Form
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 11.1 1.7 10.8 2.1 –0.08 0.72 0.88
Functional (Pre-)Academics 11.3 1.9 9.7 2.1 –0.53 0.57 0.73
School Living 10.2 1.8 10.5 2.0 0.09 0.50 0.69
Health and Safety 10.7 1.4 11.2 2.2 0.21 0.34 0.61
Leisure 10.2 1.4 11.9 2.7 0.62 0.78 0.94
Self-Care 11.0 1.8 10.5 2.0 –0.15 0.39 0.57
Self-Direction 10.6 2.6 10.4 2.1 –0.07 0.66 0.72
Social 9.0 2.4 10.3 1.9 0.37 0.80 0.85
Adaptive domain
Conceptual 105.4 11.8 99.8 9.5 –0.34 0.69 0.77
Social 99.9 11.5 103.4 11.4 0.21 0.88 0.92
Practical 104.7 10.8 100.3 9.2 –0.29 0.48 0.60
GAC 103.1 10.9 100.5 9.4 –0.17 0.75 0.84
Note. n = 19.
ABAS-3 89Validity
Table 5.24. Correlations Between the Parent and Adult Forms: Ages 16–21
Parent Form
Adult Form 
(Rated by Others)
Adaptive skill area/Composite Mean SD Mean SD Effect size r Corrected r
Adaptive skill area
Communication 7.7 2.0 7.4 2.5 –0.08 0.56 0.71
Community Use 10.1 1.9 8.3 2.5 –0.57 0.69 0.84
Functional Academics 9.4 1.7 8.7 2.3 –0.27 0.59 0.79
Home Living 8.9 1.0 9.5 2.5 0.27 0.22 0.58
Health and Safety 10.4 1.4 9.8 2.2 –0.23 0.19 0.37
Leisure 6.8 3.2 6.6 3.3 –0.04 0.85 0.84
Self-Care 10.5 1.1 11.4 2.9 0.36 0.18 0.47
Self-Direction 9.4 2.1 8.5 2.6 –0.26 0.70 0.82
Social 8.1 1.8 8.4 2.4 0.08 0.86 0.94
Work 9.8 3.1 7.6 3.8 –0.44 0.40 0.39
Adaptive domain
Conceptual 92.8 10.4 89.6 11.9 –0.20 0.85 0.92
Social 90.4 12.0 87.4 14.1 –0.16 0.93 0.96
Practical 96.2 6.3 94.2 10.6 –0.17 0.73 0.93
GAC 93.0 9.2 89.8 11.1 –0.22 0.87 0.95
Note. n = 29; n with Work = 27.
Validity
The concept of test validity has both theoretical and 
practical dimensions. The theoretical aspects of valid-
ityteacher and 
parent ratings.
126 ABAS-3 Chapter 5 Reliability and Validity
Table 5.55. Mean ABAS-3 Scaled and Composite Scores, Mixed Clinical Samples and 
Matched Control Groups: Adult Form (Self-Report) (Ages 16–89)
Mixed clinical sample Matched control group
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d
Adaptive skill area
Communication 5.1 4.0 10.6 2.6 1.66
Community Use 5.1 3.9 10.6 2.5 1.69
Functional Academics 4.9 4.1 10.3 2.5 1.63
Home Living 5.4 3.8 9.8 2.8 1.33
Health and Safety 5.4 3.9 10.3 3.1 1.41
Leisure 4.8 3.9 10.3 2.5 1.71
Self-Care 5.1 4.1 10.1 2.9 1.45
Self-Direction 4.8 3.6 10.2 2.8 1.65
Social 4.9 3.9 10.3 2.7 1.64
Work 6.9 3.6 9.9 3.4 0.85
Adaptive domain
Conceptual 70.5 21.2 100.6 12.7 1.77
Social 72.9 18.9 99.9 12.7 1.71
Practical 72.7 20.0 99.2 12.5 1.64
GAC 70.4 20.9 100.1 13.0 1.75
Note. n = 32. Wilks’ lambda = .411, F(13, 50) = 5.51, p < .001.
Table 5.56. Mean ABAS-3 Scaled and Composite Scores, Mixed Clinical Samples and 
Matched Control Groups: Adult Form (Rated by Others) (Ages 16–89)
Mixed clinical sample Matched control group
Adaptive skill area/Composite Mean SD Mean SD Cohen’s d
Adaptive skill area
Communication 4.0 3.2 11.8 2.7 2.66
Community Use 4.5 3.0 11.2 2.5 2.43
Functional Academics 4.1 2.8 11.4 2.3 2.92
Home Living 4.1 2.8 10.4 2.9 2.22
Health and Safety 4.4 3.2 11.3 2.3 2.52
Leisure 3.6 2.9 11.1 2.3 2.86
Self-Care 3.1 3.8 11.2 3.1 2.35
Self-Direction 4.4 2.9 10.9 2.5 2.38
Social 4.2 3.0 11.3 2.0 2.82
Work 4.7 3.3 9.0 5.6 0.98
Adaptive domain
Conceptual 68.8 10.8 104.8 11.3 3.25
Social 70.4 11.6 105.4 11.3 3.06
Practical 65.9 13.3 102.9 10.6 3.08
GAC 65.3 11.9 103.8 11.1 3.35
Note. n = 32. Wilks’ lambda = .206, F(13, 50) = 14.86, p < .001.
ABAS-3 127Validity
Children With Motor and Physical Impairments
Several samples of children with motor or physical 
impairments and ranging in age from 2 to 6 years 
were rated on the ABAS-II forms and compared to 
matched control groups. Children included in the 
samples either had scores in the range of clinical 
impairment on standardized measures of motor 
development, or had a physical condition that caused 
marked motor impairment. In this clinical group, 
mean GACs were 76 on the Teacher/Daycare Provider 
Form and 79 on the Parent/Primary Caregiver Form. 
Matched controls had mean GACs of 97 and 98 on the 
Teacher/Daycare Provider and Parent/Primary Care-
giver forms, respectively. As expected, children with 
motor impairments performed significantly lower 
in the Motor adaptive skill area than their matched 
controls. They also showed large deficits in the Self-
Care adaptive skill area and in the Practical adaptive 
domain when compared to matched controls, most 
likely because motor skills are needed to perform 
activities covered by the items in these areas.
Children With Receptive and/or Expressive 
Language Disorders
The ABAS-II manual reported analyses of two samples 
of children with receptive or expressive language 
disorders and ranging in age from 2 to 6 years. Mean 
ABAS-II GAC across samples was 84 for the children 
with language disorders, and mean GAC ranged 
from 99 to 102 for the matched control groups. As 
exhibited, children with receptive and/or expressive 
language disorders exhibited the greatest deficits 
in the Communication adaptive skill area. They 
also showed a large deficit in the Functional Pre-
Academics adaptive skill area when compared to 
their matched controls. Almost all adaptive skill area 
scaled scores were significantly lower than those of 
matched controls.
Children With Behavior Disorders and Emotional 
Disturbance
As reported in the ABAS-II manual, children ages 6 to 
21 diagnosed with behavior disorders or emotional 
disturbance scored significantly lower in adaptive 
skills than did matched controls. However, children 
with intellectual disability scored lower in all adap-
tive skill areas, all adaptive domains, and the GAC 
than did the children with ADHD, behavior disor-
ders, or emotional disturbance. Children with ADHD, 
behavior disorders, or emotional disturbance exhib-
ited their largest skill deficit, relative to matched 
controls, in the Self-Direction adaptive skill area. In 
comparison, individuals with intellectual disability 
generally exhibited their lowest performance in the 
Communication and Functional Academics adaptive 
skill areas.
Children Who Are Deaf or Hard of Hearing
In contrast to the other clinical studies with ABAS-II 
forms, mean GAC from a sample of children ages 5 to 
19 years diagnosed as deaf or hard of hearing did not 
differ significantly from the mean GAC of 99 for the 
matched control group. Significant differences were 
also not apparent on the adaptive domains or adap-
tive skill areas.
Children With Learning Disabilities
Across four samples of children with learning dis-
abilities and ranging in age from 5 to 21 years, mean 
ABAS-II GAC scores were significantly lower than 
those of matched control groups. Overall, the four 
learning disability groups performed most poorly in 
the Communication, Functional Academics, and Self-
Direction adaptive skill areas.
Adult Clinical Samples
The ABAS-II manual describes two adult clinical 
samples: 25 individuals diagnosed with Alzheimer’s 
disease and 18 individuals with unspecified neuro-
psychological disorders. The Alzheimer’s group, 
who ranged in age from 43 to 88 years, showed sig-
nificantly lower ABAS-II GAC and adaptive domain 
scores than did a matched control group. Scores of 
those in the mixed neuropsychological disorders 
group (ages 18 to 85 years) who rated themselves on 
the Adult Form yielded a mean GAC of 82, compared 
with a mean GAC of 100 for a matched control group. 
Scores of those in the same group rated by others on 
the Adult Form showed a wider disparity: a mean 
GAC of 67 for the neuropsychological disorders sam-
ple, compared with a mean GAC of 101 for a matched 
control group. Adaptive domain scores ranged from 
67 to 86 for the clinical samples and from 99 to 103 
for matched control groups.
128 ABAS-3 Chapter 5 Reliability and Validity
Summary
This chapter has described the psychometric 
research undertaken to support the publication of 
the ABAS-3. Reliability was examined from several 
perspectives, with the ABAS-3 adaptive skill area 
scaled scores, adaptive domain standard scores, and 
GAC scores performing well on indexes of internal 
consistency, standard error of measurement, test–
retest reliability, interrater reliability, cross-form 
consistency, and alternative-forms reliability. Confir-
matory factor analysis revealed good fit for a single-
factor model of general adaptive behavior, as well as 
for a model with three factors analogous to the Con-
ceptual, Social, and Practical adaptive domains. The 
scales and composite scores correlated in expected 
ways with scores from the ABAS-II, BASC-2, and 
Vineland-II, providing evidence of convergent valid-
ity. Finally, the ABAS-3 scores distinguish typically 
developing individuals from those with intellectual 
disability, autism spectrum disorder, and attention-
deficit/hyperactivity disorder.