Individually randomized treatments are often administered within a group setting. As a consequence, outcomes for treated individuals may be correlated due to provider effects, common experiences within the group, and/or informal processes of socialization. In contrast, it is often reasonable to regard outcomes for control participants as…

Describes the application of multilevel statistical models to the evaluation of a multi-site community-based intervention and explicates key issues in the design,analysis, and presentation of results. The initiative described, "Fighting Back, is designed to reduce the demand for illegal drugs and alcohol in a community. (SLD)

This article describes the evolution of Raymond B. Cattell's data box (covariation chart), a synoptic conception of psychological data, from its introduction in 1946. Analytical techniques and related methodologies developed from this model by Cattell and other psychological researchers are discussed. (BS)