Factorial and hierarchical cluster analysis of the Adaptive Behavior Scales (Part I & II) in a population of older people (50 years +) with severe intellectual impairment (mental handicap)

Abstract

Factorial studies of the Adaptive Behavior Scales (Nihira, 1974) are reviewed with particular reference to the extent to which different levels of aggregation of individual scores into “domains” affect the perceived factor structure. Inherent limitations of factor analysis programs include (a) absence of testing that the variables are correlated appropriately for a valid factor solution to be derived, (b) lack of external validation of the correct number of factors to be derived. Here, principal components analysis was employed separately with ABS Part 1 to yield two factors: Personal Competence and Community Competence. ABS Part 2 yielded four factors: Intermaladaptive behaviour (anti-social behaviour), Personal Maladaptation, Withdrawal, and Self-Injurious Behaviour. Cluster analysis was employed to assess the validity of these analyses.