A New Approach to the Interpretation of Test Scatter on the WISC-R

Abstract

Scatter among the WISC-R Verbal, Performance and Full Scale tests was investigated for the standardization sample (N=2200). Two indices of test scatter were analyzed: scaled-score range (a child's highest minus his lowest scaled score), and the number of tests deviating by 3 or more points from his own mean. No meaningful fluctuations in the indices were apparent when they were computed separately by age, sex, race, parental occupation, or intelligence level. Another major finding was that the WISC-R profiles of normal children exhibit much scatter, probably more than most test users realize. Normative tables were developed to enable the clinician, and the researcher, to evaluate more scientifically the test scatter for an exceptional individual or group.