MODIFICATION OF KELLY AND RICE METHOD FOR SYNERGISM TESTS

In this paper, we present a modified Kelly and Rice method for testing synergism. This approach is consistent with Berenbaum's1-3 framework for additivity. The delta method[4] is applied to obtain the estimated variance for the predicted additivity proportion. A Monte Carlo simulation study for the evaluation of the method's performance, i.e., global overall tests for synergism, is also discussed. Kelly and Rice[5] do not provide a correct test statistic because the variance is underestimated. Hence, the performance of the Kelly–Rice[5] method is generally anti-conservative, based on the simulation findings. In addition, the overall test of synergism with χ2(r) from the modified Kelly and Rice method for larger sample sizes is better than that with χ2(1) from the modified Kelly and Rice method.