手法を比較

	TGARCHモデル（Threshold GARCH）	ベクトル自己回帰 (VAR)
分野	計量経済学	計量経済学
系統	Regression model	Regression model
提唱年	1993-1994	1980
提唱者	Zakoian (1994); Glosten, Jagannathan & Runkle (1993)	Christopher A. Sims
種類	Asymmetric volatility model	Multivariate time-series model
原典	Zakoian, J.-M. (1994). Threshold heteroskedastic models. Journal of Economic Dynamics and Control, 18(5), 931-955.	Sims, C. A. (1980). Macroeconomics and Reality. Econometrica, 48(1), 1–48.
別名	Threshold GARCH, TGARCH, GJR-GARCH, asymmetric GARCH	VAR, VAR model, vector autoregressive model, multivariate autoregression
関連	6	5
概要	The Threshold GARCH (TGARCH) model extends the standard GARCH framework by allowing positive and negative return shocks to have asymmetric effects on conditional variance. Negative shocks — bad news — typically amplify volatility more than positive shocks of the same magnitude, a stylised fact known as the leverage effect. TGARCH captures this asymmetry through a threshold indicator that switches on when the previous period's shock was negative.	Vector Autoregression is a multivariate time-series model in which each variable is regressed on its own lags and the lags of all other variables in the system. Originally proposed by Sims (1980) as a data-driven alternative to large structural macroeconomic models, VAR has become the standard workhorse for dynamic analysis in empirical economics and finance.