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

Dulal K. Bhaumik, Subhash Aryal, Anup Amatya, Kush Kapur, Robert D. Gibbons

Research output: Contribution to journalArticle


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.

Original languageEnglish
Pages (from-to)11-21
Number of pages11
JournalJournal of Applied Statistical Science
Issue number1
Publication statusPublished - 1 Dec 2011



  • Hierarchical models
  • Marginal maximum likelihood
  • Power analysis
  • Type I error rate

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