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JAMA Guide to Statistics and Methods
May 5, 2020

Overlap Weighting: A Propensity Score Method That Mimics Attributes of a Randomized Clinical Trial

Author Affiliations
  • 1Department of Biostatistics and Bioinformatics, Duke University, Durham, North Carolina
  • 2Duke Clinical Research Institute, Durham, North Carolina
  • 3Department of Statistical Science, Duke University, Durham, North Carolina
JAMA. 2020;323(23):2417-2418. doi:10.1001/jama.2020.7819

Evidence obtained from clinical practice settings that compares alternative treatments is an important source of information about populations and end points for which randomized clinical trials are unavailable or infeasible.1 Unlike clinical trials, which strive to ensure patient characteristics are comparable across treatment groups through randomization, observational studies must attempt to adjust for differences (ie, confounding). This is frequently addressed with a propensity score (PS) that summarizes differences in patient characteristics between treatment groups. The PS is the probability that each individual will be assigned to receive the treatment of interest given their measured covariates.2 Matching or weighting on the PS is used to adjust comparisons between the 2 groups being compared.2,3