Evidence-appraisal glossary
Inverse Probability Weighting
A technique that reweights each participant by the inverse of their probability of receiving the treatment they actually got, creating a pseudo-population in which treatment is unrelated to the measured confounders. Comparisons in that reweighted population estimate the treatment effect.
Also called: IPW, inverse probability of treatment weighting.
Inverse probability weighting uses a model, often a propensity score, to estimate each person's chance of being treated given their characteristics. People who were unlikely to receive the treatment they got are given more weight, so underrepresented combinations count for more, which balances measured confounders across groups. It only accounts for variables you actually measured, and a handful of very large weights can make estimates unstable, so analysts inspect and sometimes trim them.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.