เปรียบเทียบวิธี

	ตัวแปรเครื่องมือในการวิจัยทางการศึกษา	Difference-in-Differences (DiD)
สาขาวิชา	การอนุมานเชิงสาเหตุ	เศรษฐมิติ
ตระกูล	Regression model	Regression model
ปีกำเนิด	1991 (canonical education application)	1994
ผู้ริเริ่ม	Angrist & Krueger (canonical 1991 education application); grounded in IV theory by Wright (1928)	Card & Krueger (canonical 1994 application); Angrist & Pischke (textbook treatment)
ประเภท	Quasi-experimental causal identification	Causal inference / panel regression
แหล่งต้นตำรับ	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 University Press. ISBN: 978-0691120355
ชื่อเรียกอื่น	IV in education, 2SLS in education, education IV, school IV estimation	diff-in-diff, DiD, Farkların Farkı (Diff-in-Diff)
ที่เกี่ยวข้อง	5	5
สรุป	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.	Difference-in-Differences is a causal-inference method that estimates the effect of an intervention by comparing how a treatment group and a control group change over time. Made famous by Card and Krueger's 1994 minimum-wage study and developed in Angrist and Pischke's Mostly Harmless Econometrics, it isolates the treatment effect as the difference between the two groups' before-after changes.