Validity of the similarities ratio as a predictor of violent behavior: data from a mentally-retarded sample

It has been proposed that a low WAIS Similarities subtest scaled score, relative to the other subtests, is associated with violent behavior. The validity of this ratio was investigated in a sample of 106 mentally-retarded Ss. The ratio of Similarities to the sum of all the subtest scores was correlated with the Violent and Destructive Behavior domain from the Adaptive Behavior Scale. A very small (r = -0.11) and statistically-nonsignificant coefficient was derived, making this the third failure to replicate or generalize the validity of this index.