Choosing the parameter for a 2 x 2 table or a 2 x 2 x 2 table analysis.

Fourteen 2 x 2 table measures of association are compared and six 2 x 2 x 2 table measures of synergism are compared. The presentation is based on a conceptual population model for the true association between the disease and the risk factor(s). Each measure is judged as to potential use and identified with the study designs under which it can be estimated. It is shown that prior information about the correct population model is required to adequately measure synergism.