Propensity score analysis is a statistical technique that is used to reduce bias in observational studies by creating a pseudo-randomized experiment. The propensity score is essentially the probability of an individual or unit being assigned to a particular treatment or exposure group, based on their observed characteristics. Researchers can then match or control for individuals with similar propensity scores to make valid comparisons between treatment groups. Propensity score analysis is commonly used in healthcare, social sciences, and economics research to estimate causal effects and make causal inferences from observational data.