New Biostatistical Guidance Document Available: Small-Sample Robust Variance Correction for GEE

Tools for ResearchThe NIH Collaboratory’s Biostatistics and Study Design Core has just published a new guidance document by Andrea Cook, PhD, of the Group Health Research Institute, on using small-sample robust variance correction for generalized estimating equations (GEE) for use in cluster-randomized trials. The document, which includes guidance on methods available in the SAS and Stata statistical analysis packages, is available directly from the NIH Collaboratory Knowledge Repository here (opens as PDF), or via the Biostatistical Guidance Documents page in the Living Textbook.

This guidance document is one in a series of research tools focused on detailed aspects of statistical design for conducting pragmatic clinical trials. Each document in this series provides a synthesis of current developments, discusses possible future directions, and, where appropriate, makes recommendations for application to pragmatic clinical research.

Cluster Randomized Trial Design Featured in JAMA’s Guide to Statistics and Methods Series

A new article published this week in JAMA describes the cluster randomized trial design. The article is part of JAMA’s Guide to Statistics and Methods series, which publishes explanations of analytic and methodologic approaches used in current research articles to help clinicians better understand the research.

In “Cluster Randomized Trials: Evaluating Treatments Applied to Groups,” Drs. William J. Meurer and Roger J. Lewis define cluster randomization, describe its advantages and limitations, and provide guidance on interpreting cluster randomized trials. The article discusses aspects of a recent cluster randomized trial, the RESTORE trial, as an example.

In RESTORE, pediatric intensive care units were randomized to assess the effects of a nurse-implemented sedation protocol for children with acute respiratory failure on mechanical ventilation. As Meurer and Lewis point out, “interventions that involve training multidisciplinary health care teams are practically difficult to conduct using individual-level randomization, as health care practitioners cannot easily unlearn a new way of taking care of patients.” Cluster randomized designs are therefore often used for this type of research, and it is important for clinicians to be able to understand and evaluate these studies.

Meurer WJ, Lewis RJ. Cluster randomized trials: evaluating treatments applied to groups. JAMA. 2015;313:2068-2069. PMID: 26010636. doi:10.1001/jama.2015.5199.