방법 비교

	정책 평가 역확률 가중치 (Policy Evaluation Inverse Probability Weighting)	Marginal Structural Model (MSM)
분야	인과추론	인과추론
계열	Regression model	Regression model
기원 연도	1952 (IPW origin); 2000s (policy evaluation application)	2000
창시자	Horvitz & Thompson (1952); extended to causal policy settings by Robins, Hernan & Brumback (2000) and Imbens & Wooldridge (2009)	James M. Robins, Miguel A. Hernan, Babette Brumback
유형	Reweighting estimator for causal policy analysis	Causal model / semiparametric weighting
원전	Imbens, G. W., & Wooldridge, J. M. (2009). Recent Developments in the Econometrics of Program Evaluation. Journal of Economic Literature, 47(1), 5-86.	Robins, J. M., Hernan, M. A., & Brumback, B. (2000). Marginal structural models and causal inference in epidemiology. Epidemiology, 11(5), 550-560.
별칭	IPW policy evaluation, propensity-weighted policy analysis, inverse probability of treatment weighting	MSM, MSM-IPTW, marginal structural Cox model, weighted structural model
관련	6	5
요약	Policy evaluation inverse probability weighting (IPW) uses estimated propensity scores to reweight observed units so that the weighted sample mimics a randomised experiment. Each unit is weighted by the inverse of its probability of receiving the policy, creating a pseudo-population in which treatment assignment is independent of observed covariates and the average treatment effect (ATE) can be read off directly.	A marginal structural model is a causal modeling framework designed to estimate the effect of a time-varying treatment in the presence of time-varying confounders that are themselves affected by prior treatment. By reweighting observations with inverse probability of treatment weights, MSMs create a pseudo-population in which confounding is eliminated, enabling unbiased estimation of causal treatment contrasts even when standard regression adjustments would fail.