Describes the loglinear model, and applies it to categorical data cross-tabulated on four dimensions. Defines contrasts similar to those of the analysis of variance and describes post hoc and planned comparison strategies. Illustrates hypothesis testing and model building for categorical data, providing guidelines for performing an analysis on…

Evaluations involving nonrandom assignment to treatment or control groups are vulnerable to an accidental or intentional confounding of a selection effect with the treatment effect. Two techniques, discriminant analysis and base expectancy analysis, permit separate estimation of the selection and treatment effects in the final results. (Author/CTM)