 
Differential Ability Scales
(DAS)
RANGE OF DAS
SUBTEST SCALED SCORES
The DAS provides a range of T scores from 20 to 80. However, this range is
not possible for all subtests at all ages of the test. Table18 shows the
ages at which a child could, on each subtest, obtain the lowest T score possible
(20) and the highest T score possible (80). For the lowest T score available
(20), none of the 17 subtests provides this scores at the lowest ages. (Verbal
Comprehension, normed for ages 2 years 6 months to 6 years 11 months, does
provide a T score of 21 at age 2 years 6 months and 20 at age 2 years 9 months).
At the upper end of scores, only 6 of the 17 subtests provide the highest T
score. For example, although the Sequential and Quantitative Reasoning subtest
provides norms from ages 5 years 0 months to 17 years 11 months, it is possible
to obtain a full range of T scores (20 to 80) only between the ages of 8 years 0
months and 13 years 5 months. A fiveyearold child who is administered this
subtest and fails all items, obtaining a raw score of 0, would obtain a T score
of 40. Conversely, a seventeenyearold child administered this subtest and
passing all items would obtain a T score of only 70.
Table18
Age at which the DAS Subtests Provide for the Lowest and Highest T
Score 
Subtest 
Total Normed Age Range 
Usual Age Range 
Age of Lowest T Score (20) 
Age of Highest T Score (80) 
Block Building 
2:64:11 
2:63:5 
3:9 
3:5 
Verbal Comprehension 
2:66:11 
2:65:11 
2:9 
5:2 
Picture Similarities 
2:67:11 
2:65:11 
3:9 
5:11 
Naming Vocabulary 
2:68:11 
2:65:11 
3:3 
6:8 
Early Number Concepts 
2:67:11 
3:65:11 
4:9 
5:8 
Copying 
3:67:11 
3:65:11 
4:6 
7:11 
Pattern Construction 
3:017:11 
3:617:11 
4:6 
14:11 
Word Definitions 
5:017:11 
6:017:11 
7:9 
17:11 
Similarities 
5:017:11 
6:017:11 
7:6 
17:11 
Matrices 
5:017:11 
6:017:11 
6:3 
13:5 
Sequential & Quantitative Reasoning 
5:017:11 
6:017:11 
8:0 
13:5 
Recall of Designs 
5:017:11 
6:017:11 
6:6 
17:11 
Matching Letterlike Forms 
4:07:11 
4:65:11 
5:9 
5:2 
Recall of Digits 
2:617:11 
3:017:11 
4:0 
13:11 
Recall of Objects 
4:017:11 
4:017:11 
5:0 
17:11 
Recognition of Pictures 
2:617:11 
3:07:11 
4:6 
7:5 
Speed of Information Processing 
5:017:11 
6:017:11 
7:6 
17:11 
Adapted from the Differential Ability Scales: Introductory and
Technical Handbook. Copyright 1990 by The Psychological Corporation.
Reproduced by permission. All rights reserved. 
The failure to have the same maximum and minimum T scores at the upper and
lower limits (i.e., a T score of 80 or 20) throughout the test may affect how
you interpret the profiles of children. On the core subtests of the Upper
Preschool battery, typically administered to children aged 3 years 6 months to 5
years 11 months, two subtests (Verbal Comprehension and Early Number Concepts)
have limited ceilings, resulting in maximum T scores of 71 and 75 respectively,
while 3 subtests (Early Number Concepts, Copying, and Pattern Construction) have
somewhat limited floor, with minimum T scores of 30, 31, and 30 respectively
(see Table19). On the core subtests of the SchoolAge Battery, typically
administered to children between the ages of 6 years 0 months and 17 years 11
months, three subtests (Pattern Construction, Matrices, and Sequential &
Quantitative Reasoning) have insufficient ceiling scores, resulting in maximum T
scores of 75, 75, and 70 respectively, while 3 subtests (Word Definitions,
Similarities, and Sequential & Quantitative Reasoning) have somewhat limited
floor, with minimum T scores of 30, 30, and 32 respectively (see Table20).
Table19
Lowest and Highest Subtest T Score Ranges on Upper Preschool Battery 
Subtest 
T Score Range at Lowest Usual Age (3:6) 
T Score Range at Highest Usual Age (5:11) 
Verbal Comprehension 
20  80 
20  71 
Picture Similarities 
21  80 
20  80 
Naming Vocabulary 
20  80 
20  80 
Early Number Concepts 
30  80 
20 75 
Copying 
31  80 
20  80 
Pattern Construction 
30  80 
20  80 
Adapted from the Differential Ability Scales: Introductory and
Technical Handbook. Copyright 1990 by The Psychological Corporation.
Reproduced by permission. All rights reserved. 
Table20
Lowest and Highest Subtest T Score Ranges on SchoolAge Battery 
Subtest 
T Score Range at Lowest Usual Age (6:0) 
T Score Range at Highest Usual Age (17:11) 
Pattern Construction 
20  80 
20  75 
Word Definitions 
30  80 
20  80 
Similarities 
30  80 
20  80 
Matrices 
21  80 
20  75 
Sequential & Quantitative Reasoning 
32  80 
20  70 
Recall of Designs 
24  80 
20  80 
Adapted from the Differential Ability Scales: Introductory and
Technical Handbook. Copyright 1990 by The Psychological Corporation.
Reproduced by permission. All rights reserved. 
RANGE OF DAS FULL SCALE IQS
The range of DAS GCA is 44 to 175. This range is not available at some ages.
For example, the highest possible GCA that adolescents who are aged 17 years 11
months can get is 156; the lowest possible GCA that children who are 2 years 6
month old can get is 53.
Because awarding T score points for no successes might be problematic,
Elliott (1990. p. 53) recommends that examiners attempt to administer subtests
from a lower level of the DAS
battery whenever
possible. This allows examiners to administer tasks that are closer to the
child's ability level. In cases where this is not possible, examiners can
convert the 0 raw scores to ability and then T scores and interpret the results
with extreme caution. One exception to the use of the 0 raw score is when the
examiner believes that the child's performance does not accurately reflect the
child's ability. In a case where a child refuses to do a task or to answer
questions, the raw score would reflect the child's unwillingness to participate
in the testing of that ability and not reflect the child's inability to do the
task. In these cases, if only one subtest was considered invalid, the examiner
might prorate the Composite based on the remaining, valid scores. When more than
one subtest is considered invalid, the examiner should omit the calculation of
the composite scores and restrict interpretation to the subtest level.
For children of very low ability, the DAS provides a procedure for
calculation of downward extensions of the GCA. Table 5 (pp. 38589) in the DAS
Administration and Scoring Manual provides the norms for obtaining
GCA scores as low as 25. In order to obtain extended GCA scores, the examiner
administers the appropriate subtests for a particular level of the DAS (e.g.,
Upper Preschool). The examiner then converts the obtained ability scores to T
scores using the usual subtest norm tables. However, the examiner uses the T
score from an appropriate Reference Age Group for the level of the
Cognitive Battery that was administered. The three Reference Age Groups
available are 2 years 6 months to 2 years 8 months (Lower Preschool
administration), 3 years 6 months to 3 years 8 months (Upper Preschool
administration), and 6 years 0 months to 6 years 2 months (SchoolAge
administration).
For example, a child of age 8 years 0 months is administered the Upper
Preschool battery rather than the usual SchoolAge battery. The child obtains
the ability scores shown in Figure 3. To calculate the T scores, the examiner
uses the norm table for the Reference Age Group (3:6  3:8) (DAS
Administration and Scoring Manual, p. 286). Using the sum of
these T scores, an Extended GCA of 35 is found in Table 5. GCA Equivalents of
Sums of T Scores for the Reference Age Group (p. 386  7).
Figure 3
Calculation of Extended GCA 
Subtest 
Ability Score 
T Score from Reference Age Group (3:6  3:8) 
Verbal Comprehension 
91 
43 
Picture Similarities 
60 
48 
Naming Vocabulary 
75 
50 
Pattern Construction 
65 
48 
Early Number Concepts 
70 
56 
Copying 
64 
59 



Sum of T scores 
304 
Extended GCA Score 
35 
This procedure allow examiners to administer the Lower Preschool battery to
children up to the age of 6 years 11months, and the Upper Preschool battery to
children up to age 13 years 11 months and still calculate T scores and Extended
GCA scores.
