Testing for imbalance of covariates in controlled experiments
- 1 December 1990
- journal article
- research article
- Published by Wiley in Statistics in Medicine
- Vol. 9 (12) , 1455-1462
- https://doi.org/10.1002/sim.4780091209
Abstract
Results of a controlled experiment are often adjusted for covariates found by a preliminary test to differ significantly between the treatment and control groups. The resulting test's true significance level is lower than the nominal level. Greater power can be achieved by always adjusting for a covariate that is highly correlated with the response regardless of its distribution between groups.This publication has 5 references indexed in Scilit:
- The control of confounding by intermediate variablesStatistics in Medicine, 1989
- Authors' replyStatistics in Medicine, 1989
- Covariate imbalance and random allocation in clinical trialsStatistics in Medicine, 1989
- CONFOUNDING CONFOUNDING1American Journal of Epidemiology, 1987
- CONFOUNDING: ESSENCE AND DETECTION1American Journal of Epidemiology, 1981