قارن الطرق

	اختبار ديكي-فولر المعزز القوي لجذر الوحدة	اختبار جذر الوحدة غير الخطي لـ ADF (اختبار KSS)
المجال	الاقتصاد القياسي	الاقتصاد القياسي
العائلة	Regression model	Regression model
سنة النشأة	1996-2001	2003
صاحب الطريقة	Ng and Perron (2001); Elliott, Rothenberg, and Stock (1996)	Kapetanios, Shin, and Snell
النوع	Unit root / stationarity test	Nonlinear unit root test
المصدر التأسيسي	Ng, S., and Perron, P. (2001). Lag length selection and the construction of unit root tests with good size and power. Econometrica, 69(6), 1519-1554.	Kapetanios, G., Shin, Y., & Snell, A. (2003). Testing for a unit root in the nonlinear STAR framework. Journal of Econometrics, 112(2), 359-379.
الأسماء البديلة	robust ADF test, HAC-corrected ADF, heteroscedasticity-robust unit root test, GLS-detrended ADF	KSS test, nonlinear unit root test, ESTAR unit root test, Kapetanios-Shin-Snell test
ذات صلة	6	6
الملخص	The Robust ADF unit root test extends the classical ADF procedure with improvements that correct for size distortions arising from heteroscedastic or serially correlated errors, and from poor lag-length selection. Drawing on GLS detrending (Elliott, Rothenberg, and Stock 1996) and modified information criteria (Ng and Perron 2001), it delivers reliable size and power in the presence of non-standard error processes common in macroeconomic and financial time series.	The Nonlinear ADF unit root test, most prominently operationalized by Kapetanios, Shin, and Snell (2003), extends the classical Augmented Dickey-Fuller test to detect mean reversion that occurs via an Exponential Smooth Transition Autoregressive (ESTAR) process. It tests the null of a unit root against a nonlinear stationary alternative, capturing adjustment dynamics that the standard linear ADF test misses.