WAIS-R short forms: Assessing the statistical significance of subtest differences

Objectives. To assist with analysis, in the individual case, of subtest profiles obtained from WAIS-R short-form administrations. Secondly, to offer a method of profile analysis for a full-length WAIS-R which is appropriate for use with age-graded scaled scores. Design. The study used a psychometric method for profile analysis (Silverstein, 1982a) which deals more effectively than alternative approaches with the problems raised by conducting multiple comparisons. Methods. A formula to compute the standard error of the difference between a subtest and mean subtest scores was applied to nine short forms and the full-length WAIS-R. The data used were derived from the WAIS-R standardization sample. Results. Tables for examining whether there are significant subtest differences in a clients WAIS-R profile are presented. Conclusions. An elegant method of analysing subtest profiles has been extended to permit its use with WAIS-R short forms. Guidance on the use of the tables is offered; the distinction between reliable and abnormal differences is highlighted.