Differential Ability Scales
The Differential Ability Scales (DAS; Elliott, 1990a) is an individually
administered battery of cognitive and achievement tests for children and
adolescents aged 2 years, 6 months through 17 years, 11 months. Because the DAS
covers such a wide age range, it is divided into three levels: Lower Preschool
(ages 2 years, 6 months through 3 years, 5 months), Upper Preschool (aged 3
years, 6 months through 5 years, 11 months), and School-Age (6 years, 0 months
through 17 years, 11 months). The DAS was designed to measure specific,
definable abilities and to provide interpretable profiles of strengths and
weaknesses. The DAS also contains three achievement tests, co-normed with the
cognitive battery, which allows direct ability-achievement discrepancy analysis.
The DAS is considered suitable for use in any setting in which the cognitive
abilities of children and adolescents are to be evaluated, although many of the
DAS subtests are not appropriate for students with severe sensory or motor
disabilities. The DAS cognitive battery yields a composite score labeled General
Conceptual Ability (GCA) that is defined as "the general ability of an
individual to perform complex mental processing that involves conceptualization
and transformation of information" (Elliott, 1990b, p. 20).
The DAS contains a total of 20 subtests
grouped into Core Cognitive, Diagnostic, or Achievement tests. The
Core Cognitive subtests are those used to compute the GCA and cluster
scores, while the Diagnostic subtests are those considered important and
useful in the interpretation of an individual's strengths and weaknesses, but
which do not assess "complex mental processing" well. The Diagnostic
subtests provide useful information without contaminating the GCA with subtests
showing low g loadings. The Lower Preschool battery consists of four core
subtests that combine to yield the GCA and two diagnostic subtests that may be
administered. The Upper Preschool battery includes six core subtests and an
additional five diagnostic subtests. The School-Age battery includes six core
subtests and three additional diagnostic subtests. For the Upper Preschool and
the School-Age batteries, the subtests not only combine to produce the GCA but
also yield two or three cluster scores. For Upper Preschool children, these
cluster scores represent Verbal and Nonverbal abilities. For School-Age
children, the cluster scores represent Verbal, Nonverbal Reasoning [fluid
reasoning (Keith et al., 1990)], and Spatial abilities. Although the
"typical" Preschool battery is given to children aged 3 years, 6
months through 5 years, 11 months and the "typical" School-Age battery
to children 6 years, 0 months through 17 years, 11 months, the Preschool and
School-Age batteries were also normed for an overlapping age range (5 years 0
months through 6 years 11 months). This overlap provides the examiner
flexibility when testing bright, younger children or less able, older children.
In these cases, subtests appropriate for the individual's abilities are
available. Examiners may choose to give either battery or one battery and
additional subtests from the other to children in the overlapping age range.
Exhibit-1 describes the subtests of the DAS.
- Verbal Comprehension: following
oral instructions to point to or move pictures and toys.
- Naming Vocabulary: naming
- Word Definitions: explaining the
meaning of each word. Words are spoken by the evaluator.
- Similarities: explaining how three
things or concepts go together, what they all are (e.g., house, tent, igloo;
love, hate, fear)
- Block Building: imitating
constructions made by the examiner with wooden blocks.
- Picture Similarities:
multiple-choice matching of pictures on the basis of relationships, both
concrete (e.g., two round things among other shapes) and abstract (e.g., map
with globe from among other round things).
- Copying: drawing pencil copies of abstract,
- Recall of Designs: drawing pencil
copies of abstract, geometric designs from memory after a 5-second view of
- Pattern Construction: copying
geometric designs with colored tiles or patterned cubes. There are time limits
and bonus points for fast work. An alternative "untimed" procedure
uses time limits, but no speed bonuses.
Nonverbal (Fluid Reasoning) Subtests
- Matrices: solving visual puzzles by
choosing the correct picture or design to complete a logical pattern.
- Sequential and Quantitative Reasoning: figuring
out the mathematical relationship that relates the numbers in each of two
pairs of numbers and applying that rule to another number to complete the
Early Number Concepts
- Early Number Concepts: oral
math questions with illustrations – counting, number concepts, and simple
- Basic Number Skills:
paper-and-pencil math computation.
- Spelling: written spelling of dictated
words, like a school spelling test.
- Word Reading: accuracy of reading
increasingly difficult words aloud from a list.
- Matching Letter-Like Forms:
multiple-choice matching of shapes that are similar to letters.
- Recall of Digits: repeating
increasingly long series of digits dictated at two digits per second.
- Recognition of Pictures:
seeing one, two, or three pictures for five seconds or four pictures for ten
seconds and then trying to find those pictures within a group of four to seven
- Recall of Objects-Immediate:
viewing a page of 20 pictures, hearing them named by the evaluator, trying to
name the pictures from memory, seeing them again, trying again to name all the
pictures, and repeating the process once more. The score is the total of all
the pictures recalled on each of the three trials, including pictures recalled
two or three times.
- Recall of Objects-Delayed: trying
to recall the pictures again on a surprise retest 15 to 20 minutes later.
- Speed of Information
Processing: the student scans rows of figures or numbers and marks
the figure with the most parts or the greatest number in each row. The score
is based on speed. Accuracy does not count unless it is very poor.