手法を比較

	ARCHモデル（Autoregressive Conditional Heteroskedasticity）	指数 GARCH (EGARCH)
分野	計量経済学	計量経済学
系統	Regression model	Regression model
提唱年	1982	1991
提唱者	Robert F. Engle	Nelson
種類	Conditional volatility model	Conditional volatility model (asymmetric GARCH variant)
原典	Engle, R. F. (1982). Autoregressive conditional heteroscedasticity with estimates of the variance of United Kingdom inflation. Econometrica, 50(4), 987–1007.	Nelson, D. B. (1991). Conditional Heteroskedasticity in Asset Returns: A New Approach. Econometrica, 59(2), 347-370.
別名	ARCH, autoregressive conditional heteroskedasticity, Engle ARCH, conditional variance model	exponential GARCH, Nelson's EGARCH, asymmetric GARCH, EGARCH — Üstel GARCH
関連	6	4
概要	The ARCH model, introduced by Robert Engle in 1982, captures time-varying volatility in financial and macroeconomic time series. It models the conditional variance of today's error as a function of past squared errors, explaining why volatile periods cluster together — a phenomenon known as volatility clustering.	EGARCH is an asymmetric GARCH variant, introduced by Nelson in 1991, that models the leverage effect in which bad news raises volatility more than good news of the same size. It captures the negative-shock asymmetry of financial return series by modelling the logarithm of the conditional variance.