Invited commentary: propensity scores

Am J Epidemiol. 1999 Aug 15;150(4):327-33. doi: 10.1093/oxfordjournals.aje.a010011.


The propensity score is the conditional probability of exposure to a treatment given observed covariates. In a cohort study, matching or stratifying treated and control subjects on a single variable, the propensity score, tends to balance all of the observed covariates; however, unlike random assignment of treatments, the propensity score may not also balance unobserved covariates. The authors review the uses and limitations of propensity scores and provide a brief outline of associated statistical theory. They also present a new result of using propensity scores in case-cohort studies.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Case-Control Studies
  • Causality*
  • Confounding Factors, Epidemiologic
  • Coronary Artery Bypass
  • Coronary Disease / surgery
  • Coronary Disease / therapy
  • Humans
  • Models, Statistical*