Intrasubtest Scatter on the WAIS–III Information Subtest and Psychometrically Defined Retrieval Deficits

Abstract

Milberg, et al. (1996) postulated that significant intrasubtest scatter on the Wechsler Information subtest reflects impaired retrieval. From a pool of 205 male referrals at a VA medical center with complete WAIS–III and WMS–III protocols, 28 participants with impaired retrieval (Group I) defined by a high Retrieval Composite score were identified. A sample (Group II) without similar evidence of impaired retrieval was matched to Group I on age, education, Full Scale IQ, race, and diagnosis. Intrasubtest scatter on the Information subtest was the same across groups (Group I M = 6.3, SD = 2.7; Group II M = 6.9, SD = 3.4). A second study identified impaired retrieval using the WMS–III Word Lists subtest. 21 participants (Group III) had impaired retrieval indicated by a Recognition scaled score being ⩾4 points higher than the Delayed Recall scaled score. A matched sample (Group IV) of VA patients without similar evidence of impaired retrieval was constituted. Intrasubtest scatter on the Information subtest did not differ across groups (Group III M = 6.6, SD = 2.4; Group IV M = 6.0, SD = 2.5). Evaluations of the retrieval deficit hypothesis should be based on responses of participants whose Information performance is characterized by abnormal amounts of intrasubtest scatter. It is possible that a specific amount of response variability must be present within the subtest before retrieval problems can be detected.