THE STEREOTYPED BEHAVIOR SCALE FOR ADOLESCENTS AND ADULTS WITH MENTAL-RETARDATION

The development of the Stereotyped Behavior Scale for adolescents and adults with mental retardation was described. Service provider staff i n three states selected 600 clients known for stereotypic behaviors an d then used 66 items to rate the frequency of occurrence of these beha viors. Items with test-retest reliability less than .45 and/or interra ter agreement less than .30 were deleted. The remaining 30 items were subjected to a principal component analysis with varimax rotation, A s ingle-factor solution emerged, which explained 24.9% of the variance. After eliminating 4 items with low factor loadings, we found that the final 26-item Stereotyped Behavior Scale had an internal consistency a lpha of .88, test-retest reliability was p(I) = .90, and interrater re liability was p(I) = .76.