Describes the use of multilevel models (MLMs) for studies in which individuals are randomized by groups to treatment condition. Uses data from the Safer Choices study, an evaluation of a theory-based multi-component program to prevent sexually transmitted diseases and pregnancy, to illustrate the application of MLMs for both continuous and…

Across conditions, differences between population parameters defined by common factor analysis and component analysis are demonstrated. Implications for data analytic and theoretical issues related to choice of analytic model are discussed. Results suggest that principal components analysis should not be used to obtain parameters reflecting latent…

Used simulation to compare the ability of maximum likelihood (ML) and generalized least-squares (GLS) estimation to provide theoretic fit in models that are parsimonious representations of a true model. The better empirical fit obtained for GLS, compared with ML, was obtained at the cost of lower theoretic fit. (Author/SLD)