Factorial validity and invariance of a self-report measure of physical activity among adolescent girls.

We examined the factorial validity and factorial invariance of the 3-day physical activity recall (3DPAR) using confirmatory factor analysis. Adolescent girls from two cohorts (N = 955, N = 1,797) completed the 3DPAR in the eighth grade; participants in Cohort 2 (N = 1,658) completed the 3DPAR again 1 year later in the ninth grade. The 3DPAR was best represented by two uncorrelated factors in Cohort 1. The two-factor, uncorrelated measurement model exhibited evidence of cross-validity between Cohorts 1 and 2. This model also exhibited configural and partial metric invariance between race and across time. Hence, the 3DPAR consisted of two uncorrelated factors underlying three indicators of both moderate and vigorous physical activity in this sample of Black and White girls across a 1-year period. The 3DPAR can be used in cross-sectional, prospective cohort and intervention studies that examine mediators and moderators of physical activity among Black and White adolescent girls.