A comparison of tests of homogeneity of odds ratios in K 2 x 2 tables.

We conducted a simulation study to determine the performance of nine procedures for testing the homogeneity of odds ratios in K 2 x 2 contingency tables. We recommend Tarone's approximate score test, based on the Mantel-Haenszel estimator of the common odds ratio, for use in practice. We also recommend a non-iterative statistic developed by Gart and based on the modified Woolf estimator of the common odds ratio for very large samples in balanced or mildly unbalanced designs. We base our recommendation of a statistic on its performance in terms of size and power in comparison with the other statistics considered.