Homogeneity Tests and Interval Estimations of Risk Differences for Stratified Bilateral and Unilateral Correlated Data

Homogeneity tests and interval estimations of the risk difference between two groups are of general interest under paired Bernoulli settings with the presence of stratification effects. Dallal [1] proposed a model by parameterizing the probability of an occurrence at one site given an occurrence at the other site. Based on this model, we propose three test statistics and evaluate their performances regarding type I error controls and powers. Confidence intervals of a common risk difference with satisfactory coverage probabilities and interval length are constructed. Our simulation results show that the score test is the most robust and the profile likelihood confidence interval outperforms other methods proposed. Data from a study of acute otitis media is used to illustrate our proposed procedures.