Variance imputation for overviews of clinical trials with continuous response.
Overviews of clinical trials are an efficient and important means of summarizing information about a particular scientific area. When the outcome is a continuous variable, both treatment effect and variance estimates are required to construct a confidence interval for the overall treatment effect. Often, only partial information about the variance is provided in the publication of the clinical trial. This paper provides heuristic suggestions for variance imputation based on partial variance information. Both pretest-posttest (parallel groups) and crossover designs are considered. A key idea is to use separate sources of incomplete information to help choose a better variance estimate. The imputation suggestions are illustrated with a data set.
Follmann
D
D
Division of Epidemiology and Clinical Applications, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892.
Elliott
P
P
Suh
I
I
Cutler
J
J
D000704:Analysis of Variance; D002986:Clinical Trials as Topic; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D004039:Diet, Sodium-Restricted; D004812:Epidemiologic Methods; D006801:Humans; D015201:Meta-Analysis as Topic