Structure of adaptive behavior: I. Replication across fourteen samples of nonprofoundly mentally retarded people.

A two-step procedure was used to investigate the dimensional structure of adaptive behavior of mildly, moderately, and severely mentally retarded people. The first step consisted of item factor analyses of the 66-item Client Development Evaluation Report for two derivation samples, each containing 3,024 subjects; results revealed a high degree of cross-sample similarity. Using the preceding results, we conducted parcel factor analyses for 14 samples of retarded people (average sample size, 676). These analyses resulted in a quite stable six-factor structure of adaptive behavior: Motor Development, Independent-Living Skills, Cognitive Competence, Social Competence, Social (or Extrapunitive) Maladaption, and Personal (or Intrapunitive) Maladaption. The implications for research and theory of the highly replicable six-factor structure of adaptive behavior were discussed.