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DAS SUBTESTS

The following description of the DAS subtests includes qualitative characteristics for g loadings, reliability, and specificity. The following definitions and criteria were used in assessing each subtest. Additional information is available elsewhere in this volume and in four valuable sources: Carroll (1993), Elliott (1997), Flanagan, Genshaft, & Harrison (1997), and McGrew & Flanagan (1998, pp. 14-25, 64-68, 71, 63-91, 92-128).

When describing the norms for each subtest, the terms usual and extended means that the subtest is appropriate for the full range of ability at that age. The term Out of level denotes ages at which the subtest is appropriate for most, but not all children.

The g Loading refers to the subtestís loading on the first unrotated factor or component in principle factor analysis. A subtest with a general factor loading of .70 or greater was considered Good; a loading of .51 to .69 Fair; and a loading of .50 or lower Poor. These are the same criteria used in The intelligence test desk reference (ITDR): Gf-Gc cross-battery assessment (Kaufman, 1979, pp. 109-110; McGrew & Flanagan, 1998, pp. 64, 72). Estimates of g loadings were taken from Tables 9.4 (p. 202), 9.7 (p. 204), and 9.11 (p. 206) of the DAS Introductory and Technical Handbook.

Reliability refers to the degree to which a test score is free from errors of measurement. A subtestís reliability was considered High if it was greater than or equal to .90, Medium if it was greater than .79 but less than .90, and Low if it was below .80. (McGrew & Flanagan, 1998, p. 64). Subtest reliabilities were found in the DAS Introductory and Technical Handbook Tables 8.1 and 8.2 (pp. 178-179).

A subtest has three types of variance: common variance (that which is shared with other subtests in the battery); specific variance (that portion of the subtestís variance that is reliable and unique to that subtest); and error variance (equal to 1 minus the reliability coefficient). We cannot interpret an ability supposedly measured by an individual subtest, unless that subtest contains a reasonable amount of reliable specific variance (specificity) and this specificity exceeds the error variance. We computed the specificity for each subtest at each age by the following procedure. The shared or common variance was first estimated by the squared multiple correlation between the specified subtest and all other subtests in the battery. Subtracting the reliability coefficient from the common or shared variance provided the estimate of specific variance for each subtest. Specificity was considered Ample if the value was equal to or above 25% of the total test variance and it exceeded the error variance, Adequate if it met only one of the two criteria noted for Ample, and Inadequate if it did not meet either of the two criteria noted for Ample. Again we followed the criteria listed in McGrew & Flanagan (1998, pp. 64-66).

The McGrew, Flanagan, and Ortiz Integrated Carroll/Cattell-Horn Gf-Gc Cross-Battery Approach Gf-Gc classifications are those proposed by McGrew & Flanagan (1998). See also Carroll (1993); Flanagan, Genshaft, & Harrison (1997); Flanagan, McGrew, & Ortiz (2000); McGrew (1997); and Woodcock (1990).

CORE SUBTESTS

Word Definitions Similarities Matrices Sequential & Quantitative Reasoning
Recall of Designs Pattern Construction Block Building Verbal Comprehension
Picture Similarities Early Number Concepts Naming Vocabulary Copying

DIAGNOSTIC SUBTESTS

Recall of Objects Recall of Digits Recognition of Pictures
Speed of Information Processing Matching Letter-Like Forms

ACHIEVEMENT TESTS

Basic Number Skills Spelling Word Reading

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