قارن الطرق

	تقييم السياسات: الفرق في الفروق (Difference-in-Differences)	مطابقة درجات الميل
المجال	الاستدلال السببي	إحصاء البحث
العائلة	Regression model	Process / pipeline
سنة النشأة	1978-2009	1983
صاحب الطريقة	Ashenfelter (1978); Heckman, LaLonde & Smith (1999); Imbens & Wooldridge (2009)	Paul Rosenbaum and Donald Rubin
النوع	Quasi-experimental / policy evaluation	Method
المصدر التأسيسي	Imbens, G. W., & Wooldridge, J. M. (2009). Recent Developments in the Econometrics of Program Evaluation. Journal of Economic Literature, 47(1), 5-86.	Rosenbaum, P. R., & Rubin, D. B. (1983). The central role of the propensity score in observational studies for causal effects. Biometrika, 70(1), 41–55.
الأسماء البديلة	policy DiD, program evaluation DiD, policy impact DiD, DiD policy assessment	PSM, propensity score weighting, covariate balance
ذات صلة	4	3
الملخص	Policy Evaluation DiD applies the difference-in-differences estimator specifically to assess the causal impact of government programs, regulations, or policy reforms. It compares outcome changes in a group exposed to the policy against a comparable untreated group, before and after the policy took effect, isolating the net policy effect from pre-existing trends and time-common shocks.	Propensity score matching (PSM) is a method for reducing confounding bias in observational studies by balancing baseline characteristics between treatment groups, simulating randomization. Developed by Rosenbaum and Rubin (1983), it estimates the probability of receiving treatment given observed covariates, then matches or weights treated and control individuals with similar treatment probabilities. Widely used in medicine, epidemiology, and policy evaluation when randomized trials are infeasible or unethical, enabling estimation of treatment effects while controlling for selection bias.