6 - Application of the Differential Ability Scales (DAS) and British Ability Scales, Second Edition (BAS II), for the assessment of learning disabilities

Summary

Introduction and overview

Two decades have passed since what was then a new test battery — the British Ability Scales (BAS; Elliott, Murray, & Pearson, 1979) — was introduced to the stable of tests for assessing cognitive abilities in children. The battery has since been further developed, resulting in the publication of the Differential Ability Scales (DAS; Elliott, 1990a) and the British Ability Scales, Second Edition (BAS II; Elliott, 1997a), which have achieved widespread acceptance and popularity in the USA and UK, respectively.

The BAS II and DAS represent an advance in cognitive assessment. In a review of the original BAS, Embretson (1985) stated: ‘The BAS is an individual intelligence test with greater scope and psychometric sophistication than the major American individual tests. The test development procedures and norms are laudatory’ (p. 232). In another review, Wright and Stone (1985) stated that the BAS ‘is a significant advance in mental measurement … Its form and function are a model for contemporary test builders and a preview of the future of test construction’ (p. 232). Kamphaus (1993), in reviewing the DAS, wrote: ‘There is every indication that the developers of the DAS erred in the direction of quality at every turn. The manual is extraordinarily thorough, the psychometric properties are strong, and the test materials are of high quality’ (pp. 320–1).