A study uses propensity score matching to control for confounding in a retrospective cohort. The propensity score is the:

• A Probability of having the outcome given the observed covariates
• B Inverse of the probability of treatment weighted by disease risk
• C Ratio of the probability of exposure to the probability of non-exposure
• D Conditional probability of receiving the exposure given the observed confounders ✓

Explanation

The propensity score is defined as the conditional probability of receiving a particular treatment/exposure given the observed baseline covariates (confounders). Propensity score matching pairs exposed and unexposed individuals with similar propensity scores, creating comparable groups and reducing confounding — mimicking randomisation. It does not estimate the probability of the outcome, nor is it an inverse probability weight per se (though IPTW is a related method). It is distinct from the odds of exposure.

Reference: Park's Textbook of Preventive and Social Medicine, 27th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.