Common risk difference test and interval estimation of risk difference for stratified bilateral correlated data


Chang-Xing Ma, Xi Shen, Guo-Liang Tian

Introduction


Bilateral correlated data are often encountered in ophthalmologic (or otolaryngologic) studies, in which each unit contributes information for paired organs to the studies, and the measurements from such paired organs are generally highly correlated. Various statistical methods have been developed to tackle intra-class correlation on bilateral correlated data analysis. In practice, it is important to adjust the effect of confounder on statistical inference, since either ignoring the intra-class correlation or confounding effect may lead to biased inference. In this article, we propose three test procedures for testing common risk difference for stratified bilateral correlated data in the basis of equal correlation model assumption. Five interval estimation of common difference of two proportions are derived. The performance of proposed test procedures and interval estimation is examined through Monte Carlo simulation. The simulation results show that the score test statistics outperforms other statistics in the sense that it produces robust type I error with high power. Score confidence interval with respect to score test statistics performs satisfactorily in terms of good coverage rate with reasonable interval width. One example from an otolaryngologic study is given to illustrate our methodologies.

References
1. Testing homogeneity of difference of two proportions for stratified correlated paired binary data
2. Common risk difference test and interval estimation of risk difference for stratified bilateral correlated data


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