قارن الطرق

	نموذج ARCH ذو الانقطاع الهيكلي	نموذج EGARCH (نموذج التباين الشرطي المتغير الأسي)
المجال	الاقتصاد القياسي	الاقتصاد القياسي
العائلة	Regression model	Regression model
سنة النشأة	1982–1990	1991
صاحب الطريقة	Engle (1982) for ARCH; Lamoureux & Lastrapes (1990) for break-adjusted variance persistence	Daniel B. Nelson
النوع	Volatility model with regime change	Volatility / conditional variance model
المصدر التأسيسي	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.
الأسماء البديلة	ARCH with structural breaks, break-adjusted ARCH, regime-switching ARCH, SB-ARCH	Exponential GARCH, EGARCH, Nelson EGARCH, log-GARCH
ذات صلة	5	6
الملخص	The Structural Break ARCH model extends Engle's (1982) Autoregressive Conditional Heteroscedasticity framework by explicitly accounting for abrupt, permanent shifts in the conditional variance process. Ignoring structural breaks in variance causes ARCH parameters to appear spuriously persistent, so incorporating break dummies or regime-specific parameters yields more accurate volatility estimates and better model fit.	The Exponential GARCH (EGARCH) model, introduced by Nelson (1991), extends the standard GARCH framework by modelling the logarithm of conditional variance. This ensures variance is always positive without parameter constraints and, crucially, allows negative and positive shocks to have asymmetric effects on volatility — capturing the well-known leverage effect in financial markets.