Examining the Validity and Reliability of Measures for Individual-Level Constructs Related to Implementation of School-Based Physical Activity Approaches.

Valid and reliable measures are important to understanding the implementation of physical activity approaches in schools. The study purpose is to examine the psychometric properties of measures of individual-level constructs (knowledge, attitudes, outcome expectations, self-efficacy, innovativeness, and support) in the context of implementing school-based physical activity approaches. We collected data from a sample of elementary school employees (administrators, classroom teachers, physical educators, and support staff) from an urban school district in southeast Texas. Confirmatory factor analysis (CFA) models were used to examine structural validity. We also examined correlations between constructs to assess discriminant and convergent validity. Last, we used a CFA-based approach to examine scale reliability. The analytic sample consisted of 205 employees. CFA results for each individual measure revealed good-fitting models for most measures (χ² (df) >0.05, RMSEA <0.08, CFI >0.90, TLI >0.90, SRMR≤0.07). A combined model that included all the measures also indicated good fit across indices: χ²(306) = 485, p <0.001; RMSEA = 0.05, CFI = 0.93, TLI = 0.92, SRMR = 0.07. All correlations between constructs were <0.70, and all but one construct (innovativeness) demonstrated moderate correlations with support for classroom-based physical activity approaches (>0.30). In addition, reliability point estimates were all >0.70. The measures tested in this study were found to have good reliability, as well as good structural, discriminant, and convergent validity. These measures are useful in efforts to better understand how individual-level constructs relate to implementation behaviors for physical activity approaches in schools.