เปรียบเทียบวิธี

	การทดสอบยาหลอกสำหรับผลกระทบของการรักษาที่แตกต่างกัน	Difference-in-Differences (DiD)
สาขาวิชา	การอนุมานเชิงสาเหตุ	เศรษฐมิติ
ตระกูล	Regression model	Regression model
ปีกำเนิด	2000s–2010s	1994
ผู้ริเริ่ม	Rosenbaum (placebo test concept); Athey & Imbens (HTE estimation framework)	Card & Krueger (canonical 1994 application); Angrist & Pischke (textbook treatment)
ประเภท	Validation / falsification test	Causal inference / panel regression
แหล่งต้นตำรับ	Imbens, G. W., & Rubin, D. B. (2015). Causal Inference for Statistics, Social, and Biomedical Sciences: An Introduction. Cambridge University Press. ISBN: 978-0521885881	Angrist, J. D., & Pischke, J.-S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton University Press. ISBN: 978-0691120355
ชื่อเรียกอื่น	HTE placebo test, heterogeneous-effect placebo check, subgroup placebo test, CATE placebo validation	diff-in-diff, DiD, Farkların Farkı (Diff-in-Diff)
ที่เกี่ยวข้อง	3	5
สรุป	A placebo test for heterogeneous treatment effects is a falsification strategy used to validate whether estimated variation in treatment effects across subgroups or covariate values is genuine rather than an artifact of model specification, overfitting, or coincidental patterns. By applying the same estimation procedure to pseudo-treatments, fake outcomes, or subgroups that logically should not differ, researchers check that observed heterogeneity reflects real causal variation.	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.