مقایسهٔ روش‌ها

	آزمون DF-GLS: آزمون ریشه واحد دیک-فولر با روندزدایی GLS	آزمون ریشه واحد بهینه نقطه‌ای ERS	آزمون ایستایی KPSS
حوزه	اقتصادسنجی	اقتصادسنجی	اقتصادسنجی
خانواده	Hypothesis test	Hypothesis test	Regression model
سال پیدایش	1996	1996	1992
پدیدآور	Elliott, Rothenberg & Stock	Elliott, Rothenberg & Stock	Kwiatkowski, Phillips, Schmidt & Shin
نوع	One-sided t-test on GLS-detrended series	One-sided parametric unit-root test	Stationarity test (reverse of unit-root tests)
منبع بنیادین	Elliott, G., Rothenberg, T. J., & Stock, J. H. (1996). Efficient tests for an autoregressive unit root. Econometrica, 64(4), 813–836.	Elliott, G., Rothenberg, T. J., & Stock, J. H. (1996). Efficient tests for an autoregressive unit root. Econometrica, 64(4), 813–836.	Kwiatkowski, D., Phillips, P. C. B., Schmidt, P., & Shin, Y. (1992). Testing the null hypothesis of stationarity against the alternative of a unit root. Journal of Econometrics, 54(1–3), 159–178.
نام‌های دیگر	Elliott-Rothenberg-Stock test, ERS unit-root test, GLS-detrended Dickey-Fuller test, DF-GLS birim kök testi	ERS P-test, Point-Optimal Unit-Root Test, ERS PT statistic, ERS Nokta-Optimal Birim Kök Testi	Kwiatkowski-Phillips-Schmidt-Shin test, stationarity test, KPSS durağanlık testi
مرتبط	3	3	4
خلاصه	The DF-GLS test, introduced by Elliott, Rothenberg, and Stock (1996), is a modified augmented Dickey-Fuller procedure that applies generalized least squares (GLS) detrending before the standard unit-root regression. By removing deterministic components under a local alternative rather than the null hypothesis, the test achieves near-optimal power for detecting stationarity in time series, making it the preferred unit-root test in applied econometrics when a trend or intercept is present.	The Elliott-Rothenberg-Stock (ERS) Point-Optimal test, introduced in their landmark 1996 Econometrica paper, is a near-efficient parametric procedure for testing whether a univariate time series contains a unit root. By first applying GLS detrending at a carefully chosen local-to-unity value and then computing a likelihood-ratio-type statistic, it achieves power close to the Gaussian power envelope—making it one of the most powerful unit-root tests available to applied econometricians.	The KPSS test, introduced by Kwiatkowski, Phillips, Schmidt and Shin in 1992, tests the null hypothesis that a series is stationary against the alternative that it contains a unit root — the reverse of the ADF and Phillips-Perron tests. By flipping the burden of proof, it is designed to be used alongside unit-root tests so that the two can confirm one another and expose ambiguous, borderline cases.