Diagnostic utility of the number of WISC-III subtests deviating from mean performance among students with learning disabilities

This paper examined the diagnostic utility of subtest variability, as repre sented by the number of subtests that deviate from examinees' mean IQ score s, for identifying students with a learning disability (LD). Participants c onsisted of the 2,200 students in the WISC-III normative sample and 684 stu dents (Mdn grade = 5: M age = 10.8) identified as LD. The number of subtest s deviating from examinees' Verbal, Performance, and Full Scale IQ by +/-3 points for normative and exceptional samples were contrasted via Receiver O perating Curve (ROC) analyses. Results indicated that LD students did not d iffer from normative sample children at levels above chance. It was conclud ed that deviation of individual subtest scores from mean IQ scores has no d iagnostic utility for hypothesizing about students with learning disabiliti es. (C) 2000 John Wiley & Sons, Inc.