The Self Description Questionnaire III: Testing for Equivalent Factorial Validity across Ability

Confirmatory factor analysis (CFA; LISREL) was used to (a) validate the Self Description Questionnaire III (SDQ III) subscales measuring general, school, English, and mathematics self-concepts for a sample of 898 (285 low track, 613 high track) grades 11 and 12 students, and (b) test the equivalency of the factor structure across academic track. The results confirmed a 4-factor structure and revealed all factor loadings and covariances to be invariant across groups; 11 of 21 uniquenesses were noninvariant. Although, in a strict statistical sense, the differentially reliable items bore implications of bias in favor of the high track, these discrepancies, on the basis of absolute values, were judged to be of little practical significance. Overall, in light of the stringency of LISREL CFA procedures in general, and those used in this study in particular, the SDQ III demonstrated exceptionally superior psychometric properties.