Abstract: Although many studies have attempted to identify mediators and moderators of changes in physical activity involvement, the literature is inconclusive regarding which variable(s) relate to physical activity behavior change. The Cooper 2001 Conference series dedicated a session to discussing measurement and statistical methods that could contribute to advancing this research agenda. This article focuses on four such methodologic approaches: qualitative; psychometric; latent-variable, structural equation modeling; and multilevel modeling. The article presents a brief overview of these methods and discusses potential advantages and limitations of using them.