Bandingkan kaedah

	GMM Sistem Teguh	Kaedah Pemboleh Ubah Instrumental (IV) untuk Inferensi Kausal
Bidang	Ekonometrik	Ekonomi Kesihatan
Keluarga	Regression model	Process / pipeline
Tahun asal	1998–2005	1990s (modern applications)
Pengasas	Blundell & Bond (1998); robustness corrections by Windmeijer (2005)	Angrist & Pischke (applied econometrics); rooted in econometric theory
Jenis	Panel data GMM estimator	Method
Sumber perintis	Blundell, R., & Bond, S. (1998). Initial conditions and moment restrictions in dynamic panel data models. Journal of Econometrics, 87(1), 115–143.	Angrist, J. D., & Pischke, J. S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton: Princeton University Press.
Alias	system GMM with robust standard errors, two-step system GMM, Blundell-Bond robust estimator, robust S-GMM	IV, two-stage least squares, TSLS, causal estimation
Berkaitan	5	3
Ringkasan	Robust System GMM is a two-step panel data estimator that combines the difference and levels moment conditions of Blundell and Bond (1998) with Windmeijer's (2005) finite-sample correction to the two-step variance, producing valid inference even in short panels with a persistent dependent variable, individual fixed effects, and potentially endogenous regressors.	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.