مقایسهٔ روش‌ها

	متغیرهای ابزاری در پژوهش‌های آموزشی	روش متغیرهای ابزاری (IV) برای استنتاج علی
حوزه	استنتاج علّی	اقتصاد سلامت
خانواده	Regression model	Process / pipeline
سال پیدایش	1991 (canonical education application)	1990s (modern applications)
پدیدآور	Angrist & Krueger (canonical 1991 education application); grounded in IV theory by Wright (1928)	Angrist & Pischke (applied econometrics); rooted in econometric theory
نوع	Quasi-experimental causal identification	Method
منبع بنیادین	Angrist, J. D., & Krueger, A. B. (1991). Does Compulsory School Attendance Affect Schooling and Earnings? Quarterly Journal of Economics, 106(4), 979-1014.	Angrist, J. D., & Pischke, J. S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton: Princeton University Press.
نام‌های دیگر	IV in education, 2SLS in education, education IV, school IV estimation	IV, two-stage least squares, TSLS, causal estimation
مرتبط	5	3
خلاصه	Instrumental variables (IV) estimation is a quasi-experimental strategy for isolating the causal effect of schooling or educational interventions when assignment to treatment is confounded by unobserved factors. Pioneered in education economics by Angrist and Krueger's use of quarter-of-birth as an instrument for compulsory schooling, IV finds a source of exogenous variation in exposure to education and uses only that variation to estimate outcomes such as earnings, test scores, or attainment.	Instrumental variables (IV) is an econometric method to estimate causal effects when treatment or exposure is not randomly assigned and confounding is severe or unmeasured. IV relies on a third variable (instrument) that influences treatment but does not directly affect the outcome, allowing researchers to isolate the causal effect from the noise of confounding. Developed extensively in econometrics (Angrist & Pischke, 1990s–2000s), IV methods are increasingly used in health economics and health services research to leverage natural experiments and policy changes.