DUNCAN, S. C., T. E. DUNCAN, L. A. STRYCKER, and N. R. CHAUMETON. A multilevel approach to youth physical activity research. Exerc. Sport Sci. Rev., Vol. 32, No. 3, pp. 95–99, 2004. Social environment factors are hypothesized to interact with individual-level factors to influence youth physical activity. Multilevel analytic approaches are ideal for examining the influence of the social environment on youth physical activity as they allow examination of research questions across multiple contexts and levels ( e.g. , individual, family, and neighborhood levels).