Separation of Competency and Affect Components of Multiple Dimensions of Academic Self-Concept: A Developmental Perspective.

Based on the Shavelson, Hubner and Stanton (1976) model of self-concept, Marsh (1988, 1989, 1990, 1993) developed the set of Self Description Questionnaires (SDQ) to measure multiple dimensions of self-concept for preadolescent primary school students (SDQ-I), adolescent high school students (SDQ-II), and late adolescents and young adults (SDQ-III). The set of three SDQ instruments have provided particularly strong tests of the Shavelson et al. model, and have been evaluated to be among the best multidimensional instruments in terms of psychometric properties and construct validation research (Hattie, 1992; Byrne, 1996; Boyle, 1994; Wylie, 1989). In this study we consider the three academic scales (Reading, Math, School) from the normative archive of the preadolescent (SDQ-I) instrument that are defined by responses to eight positively worded items four competency items (e.g., I am good at..) and four affective items (e.g., I like..).