Assessing Covariate Balance with Small Sample Sizes.

ABSTRACT: Propensity score adjustment addresses confounding by balancing covariates in subject treatment groups through matching, stratification, or weighting. Diagnostics test the success of adjustment. For example, if the standardized mean difference (SMD) for a relevant covariate exceeds a threshold like 0.1, the covariate is considered imbalanced and the study may be invalid. Unfortunately, for studies with small or moderate numbers of subjects, the probability of falsely rejecting the validity of a study because of chance imbalance-the probability of asserting imbalance by using a cutoff for SMD when no underlying imbalance exists-can be grossly larger than a given nominal level like 0.05. In this paper, we illustrate that chance imbalance is operative in real-world settings even for moderate s

SUBMITTER: Hripcsak G 

PROVIDER: S-EPMC11071580 | biostudies-literature | 2025 Feb

REPOSITORIES: biostudies-literature