Differential Item Functioning Analysis Of The Physical Activity Enjoyment Scale

Abstract

BACKGROUND: Enjoyment is a commonly reported motivation for engaging in physical activity and may be a key mediator of exercise promoting interventions for teens. Given the burden of physical inactivity in the US, identification of correlates and potential targets of intervention to promote activity are needed. The Physical Activity Enjoyment Scale (PACES) represents a promising tool to evaluate patterns of physical activity and sedentary behavior among teens. Continued validation for use with multi-ethnic teens is needed, particularly among Hispanic teens who may be characterized by risk factors associated with lower engagement in physical activity and higher sedentary behavior. METHOD: A school-based sample of 9th Grade Hispanic (N = 1605; mean age = 14.6 years, SD = .41) and Non-Hispanic White (N = 544; mean age = 14.6 years, SD = .39) students completed in-classroom self-report measures of physical activity (PA), sedentary behavior (SED), and the PACES. Full Information Maximum likelihood confirmatory factor analysis and item response models (IRM) of the Positive and Negative PACES subscales assessed construct validity and Differential Item Functioning (DIF) of the 14-item PACES among Latino and Non-Latino adolescents. RESULTS: Non-parametric IRM suggested modifications to the response format for negatively worded subscale of the PACES. A two-factor model reflecting both positive and negative subscales provided better fit than a unidimensional model (X2= 4755.0, p<0.001). Loadings on primary factors ranged from 0.87-0.94 for positive and 0.78-0.96 for negative experiences subscales. Internal consistency estimates were 0.95 and 0.90 for positive and negative scales, respectively. DIF analyses supported measurement invariance and construct validity of both subscales across Hispanic and Non-Hispanic White respondents. PACES-Positive and PACES-Negative maintained significant correlations with levels of physical activity (r=0.38 & r=-0.31, respectively) and moderate to vigorous physical activity (r=0.31 & r=-0.19, respectively). CONCLUSIONS: We found support for the construct validity, concurrent validity and consistency of measurement of the 14-item PACES provides for use in comparing positive and negative experiences of exercise among both Non-Hispanic White and Hispanic teens.