Power Analysis of Trials with Multilevel Data is a valuable reference for anyone who wants to perform power calculations on trials with hierarchical data. It provides a thorough overview of power analysis, familiarizing you with terminology and notation, outlining the key concepts of statistical power and power analysis, and covering all common hierarchical designs.

Mirjam Moerbeek is an associate professor at Utrecht University, the Netherlands. She obtained her master's degree (cum laude) in biometrics from Wageningen Agricultural University in 1996 and her PhD in applied statistics from Maastricht University in 2000. She has received prestigious research grants from the Netherlands' Organisation for Scientific Research (NWO) as well as grants to hire PhD students. Her research interests are statistical power analysis and optimal experimental design, especially for hierarchical and survival data. She was involved in organizing a colloquium and class on cost-efficient and optimal designs for the Royal Netherlands Academy of Arts and Sciences (KNAW) and is a joint organizer of the biennial International Conference on Multilevel Analysis.

Steven Teerenstra received his MSc and PhD in mathematics at Radboud University in 1996 and 2004, respectively, as well as his MSc in theoretical physics in 2006. He is currently a biostatistician at Radboud University Nijmegen Medical Center, involved in research, consultation and conduct of cluster randomized trials. He is appointed assessor of statistics and methodology at the Dutch Medicines Evaluation Board and a member of the Biostatistics Working Party at the European Medicines Agency.

List of figures. List of tables. Preface. Introduction. Multilevel statistical models. Concepts of statistical power analysis. Cluster randomized trials. Improving statistical power in cluster randomized trials. Multisite trials. Pseudo cluster randomized trials. Individually randomized group treatment trials. Longitudinal intervention studies. Extensions: three levels of nesting and factorial designs. The problem of unknown intraclass correlation coefficients. Computer software for power calculations. References. Author Index. Subject Index.