Simple improved confidence intervals for comparing matched proportions.

For binary matched-pairs data, this article discusses interval estimation of the difference of probabilities and an odds ratio for comparing 'success' probabilities. We present simple improvements of the commonly used Wald confidence intervals for these parameters. The improvement of the interval for the difference of probabilities is to add two observations to each sample before applying it. The improvement for estimating an odds ratio transforms a confidence interval for a single proportion. Copyright (c) 2004 John Wiley & Sons, Ltd.