手法を比較

	因果推論のための操作変数（IV）法	空間ラグモデル（SAR / 空間自己回帰）
分野	医療経済学	空間分析
系統	Process / pipeline	Regression model
提唱年	1990s (modern applications)	1988
提唱者	Angrist & Pischke (applied econometrics); rooted in econometric theory	Anselin (textbook formalisation); LeSage & Pace
種類	Method	Spatial autoregressive regression
原典	Angrist, J. D., & Pischke, J. S. (2009). Mostly Harmless Econometrics: An Empiricist's Companion. Princeton: Princeton University Press.	Anselin, L. (1988). Spatial Econometrics: Methods and Models. Kluwer Academic.
別名	IV, two-stage least squares, TSLS, causal estimation	SAR model, spatial autoregressive model, spatial lag, Uzamsal Gecikme Modeli (SAR / Spatial Lag)
関連	3	5
概要	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.	The Spatial Lag Model is an autoregressive regression that assumes spatial dependence in the dependent variable itself: the outcome values of neighbouring units enter the model as an explanatory term (ρWy). It was formalised in Anselin's Spatial Econometrics (1988) and developed further by LeSage and Pace (2009), and it decomposes spillover effects into direct, indirect, and total impacts.