The Prevention and Treatment of Missing Data in Clinical Trials

Missing data in clinical trials can have a major effect on the validity of the inferences that can be drawn from the trial. This article reviews methods for preventing missing data and, failing that, dealing with data that are missing. Background Missing data have seriously compromised inferences from clinical trials, yet the topic has received little attention in the clinical-trial community. 1 Existing regulatory guidances 2 – 4 on the design, conduct, and analysis of clinical trials have little specific advice on how to address the problem of missing data. A recent National Research Council (NRC) report 5 on the topic seeks to address this gap, and this article summarizes some of the main findings and recommendations of that report. The authors of this article served on the panel that prepared the report. Missing data have seriously compromised inferences from clinical trials. 1 For example, . . .