Sample size determination for between group comparisons in mixed-effects logistic regression models for analysis of longitudinal data

In this article we consider the problem of sample size determination for two-level mixed-effects logistic regression models for the analysis of longitudinal data. In this case, level 1 represents measurement occasion and level 2 represents subject. We provide an algorithmfor sample size requirements (i.e., power characteristics) for a test of the treatment-by-time interaction and overall time trend that strictly maintains the type I error rate close to the nominal level. The methodology is illustrated both via simulation and an example from a now classic psychiatric randomized clinical trial.