Propensity-Score Matching: The “Devil is in the Details” Where More May Be Hidden Than You Know

Propensity-score matching has been used with increasing frequency in the analyses of non-prespecified subgroups of randomized clinical trials as well as in retrospective analyses of clinical trial data sets, registries, observational studies, electronic medical record analyses, and more. Propensity- matching attempts to adjust post hoc for recognized unbalanced factors at baseline such that the data once analyzed will hopefully approximate or indicate what a prospective randomized data set would have shown – the latter being the “gold standard” for comparing two or more therapies.