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Differential Ability Scales (DAS)

Step-by-step Analysis

Step Five: Narrow Ability Hypotheses

  • Identify the narrow abilities assessed and any relevant differences between them

As seen from the previous discussion, despite the fact that the subtests within each of the DAS clusters measure the same broad ability, one should not be surprised to find within-cluster differences. When interpreting clusters found to have divergent subtests, examiners may generate hypotheses relevant to the subtests themselves. Knowing that Word Definitions and Similarities are both measures of Verbal ability on the School-Age DAS and also knowing that the first measures that ability through the use of Lexical Knowledge while the second measures it through Language Development provides plausible explanations for differing scores. Flanagan, McGrew, and Ortiz (2000) and McGrew and Flanagan (1998) provide descriptions of each broad and narrow ability for the major cognitive assessment batteries, including the DAS.

Table XXX-24

DAS Subtests and Proposed Narrow Abilities

Verbal Subtests

Narrow Abilities

Verbal Comprehension

Language Development

Naming Vocabulary

Lexical Knowledge

Word Definitions


Lexical Knowledge



Language Development

Nonverbal/Spatial Subtests

Block Building


Picture Similarities



Visual Memory

Recall of Designs


Visual Memory

Pattern Construction


Spatial Relations

Nonverbal (Fluid Reasoning) Subtests




Sequential and Quantitative Reasoning


Quantitative Reasoning

Early Number Concepts

Early Number Concepts

Math Achievement

Diagnostic Subtests

Matching Letter-Like Forms


Recall of Digits


Memory Span

Recognition of Pictures

Visual memory

Recall of Objects-Immediate


Visual memory

Speed of Information Processing


Mental Computational Speed

Adapted from Appendix A, pp. 445 453, The Intelligence Test Desk Reference (ITDR): Gf-Gc Cross-Battery Assessment (McGrew & Flanagan, 1998).

Shaded subtests are those typically administered in the School-Age Battery

Additional data may be necessary to reach a meaningful and trustworthy interpretation. When a significant and unusual difference between subtests leads you to interpret narrow abilities rather than the broad ability represented by the cluster as a whole, you are attempting to interpret relatively unreliable, individual subtests. You will probably need to use other tests of the same abilities to more fully understand the student's strengths and weaknesses within the broad ability. Detailed descriptions of abilities measured by other major intelligence test batteries (e.g., WISC-III and SB:FE) elsewhere in this web site and the tables in Flanagan, McGrew, and Ortiz (2000), Flanagan and Ortiz (2000), and McGrew and Flanagan (1998) allow the examiner to select additional tests to complete the measurement of unusually scattered narrow abilities within a broad ability classification.


Step Six