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 are presented. They are based on conditional and unconditional approaches using the 'exact' (binomial) test. An approximate procedure is suggested to estimate the sample size for parameter values that do not correspond exactly with table entries. The procedure utilizes a minor modification of the large-sample formula given by Connett et al. A practical strategy for estimating the overall sample size in the presence of a nuisance parameter (the proportion of discordant pairs) is recommended. An example from a proposed clinical trial is given.