So sánh phương pháp

	Kiểm định Đặc tả Hausman Phi tuyến	Phương pháp Biến Công cụ (IV) cho Suy luận Nhân quả
Lĩnh vực	Kinh tế lượng	Kinh tế học y tế
Họ	Regression model	Process / pipeline
Năm ra đời	1978 (nonlinear extension developed through 1980s–1990s)	1990s (modern applications)
Người khởi xướng	Jerry A. Hausman	Angrist & Pischke (applied econometrics); rooted in econometric theory
Loại	Specification / endogeneity test	Method
Công trình gốc	Hausman, J. A. (1978). Specification tests in econometrics. Econometrica, 46(6), 1251–1271.	Angrist, J. D., & Pischke, J. S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton: Princeton University Press.
Tên gọi khác	Hausman specification test (nonlinear), nonlinear endogeneity test, Wu-Hausman test (nonlinear), NL-Hausman test	IV, two-stage least squares, TSLS, causal estimation
Liên quan	3	3
Tóm tắt	The Nonlinear Hausman test extends Hausman's (1978) endogeneity specification test to nonlinear models such as probit, logit, Tobit, and count-data regressions. It tests whether suspected regressors are endogenous — i.e., correlated with the error term — in a model where the outcome or the relationship is inherently nonlinear, ensuring that IV-corrected estimates are necessary.	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.