Assessing Group Effects

This article examines the relationship between two methods for detecting group effects in nonexperimental data: covariance analysis and contextual analysts. The examination shows that contextual effects are a special case of the group effect obtained in covariance analysis. This finding implies that (1) the group effect of covariance analysis provides an upper limit for contextual effects, (2) covariance analysis is more directly applicable in exploratory work, while contextual analysis is more directly applicable in causal analysis, and (3) both contextual and covariance analysis are required for a complete accounting of group effects.