The NIH Collaboratory Biostatistics/Study Design Core has released a new guidance document concerning the use of frailty models in the setting of cluster-randomized trials (CRTs). This guidance, the fifth in a series from the Core, outlines considerations affecting power calculations in frailty models, as well as issues raised by the use of logistic regression models for time-to-event versus dichotomous outcomes in CRTs .

The guidance document can be found under Biostatistical Guidance Documents on the Tools for Research page on the Living Textbook, or accessed directly here (PDF).