Physical Self Description Questionnaire: stability and discriminant validity.

The Physical Self-Description Questionnaire (PSDQ) is a multidimensional, physical self-concept instrument designed to measure 11 scales: Strength, Body Fat, Activity, Endurance/Fitness, Sports Competence, Coordination, Health, Appearance, Flexibility, Global Physical Self-concept, and Global Esteem. High school students completed the PSDQ on four occasions over a 14-month period. Across the 11 PSDQ scales, the internal consistency at each occasion was good (median alpha = .92) and the stability over time varied from median r = .83 for a 3-month period to median r = .69 for the 14-month period. The data were used to demonstrate the application of confirmatory factor-analysis models of multitrait-multimethod (MTMM) data (with occasions as the multiple methods), which supported the discriminant validity of the PSDQ scales. Augmented MTMM models that included two field tests of cardiovascular endurance provided additional support for the construct validity of PSDQ responses and interpretation of the MTMM models. These results contribute to the growing body of support for the construct validity of physical-self-concept responses and illustrate the application of CFA MTMM models.