EXACT CONDITIONAL AND UNCONDITIONAL SAMPLE-SIZE FOR PAIR-MATCHED STUDIES WITH BINARY OUTCOME - A PRACTICAL GUIDE

Tables of sample sizes for pair-matched studies with binary outcome ar e presented. They are based on conditional and unconditional approache s using the 'exact' (binomial) test. An approximate procedure is sugge sted to estimate the sample size for parameter values that do not corr espond exactly with table entries. The procedure utilizes a minor modi fication of the large-sample formula given by Connett et al. A practic al strategy for estimating the overall sample size in the presence of a nuisance parameter (the proportion of discordant pairs) is recommend ed. An example from a proposed clinical trial is given.