เปรียบเทียบวิธี

	การทดสอบ KPSS แบบไม่เชิงเส้น	การทดสอบรากหน่วย Augmented Dickey-Fuller (ADF)	การทดสอบภาวะอยู่กับที่ของ KPSS
สาขาวิชา	เศรษฐมิติ	เศรษฐมิติ	เศรษฐมิติ
ตระกูล	Regression model	Regression model	Regression model
ปีกำเนิด	2006	1979	1992
ผู้ริเริ่ม	Becker, Enders & Lee	David A. Dickey & Wayne A. Fuller	Kwiatkowski, Phillips, Schmidt & Shin
ประเภท	Stationarity test (null: stationary)	Unit-root test for stationarity	Stationarity test (reverse of unit-root tests)
แหล่งต้นตำรับ	Becker, R., Enders, W., & Lee, J. (2006). A stationarity test in the presence of an unknown number of smooth breaks. Journal of Time Series Analysis, 27(3), 381-409.	Dickey, D. A., & Fuller, W. A. (1979). Distribution of the estimators for autoregressive time series with a unit root. Journal of the American Statistical Association, 74(366a), 427–431.	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.
ชื่อเรียกอื่น	KPSS nonlinearity test, nonlinear stationarity test, flexible Fourier KPSS, NL-KPSS	ADF test, Dickey-Fuller test, unit root test, Genişletilmiş Dickey-Fuller testi	Kwiatkowski-Phillips-Schmidt-Shin test, stationarity test, KPSS durağanlık testi
ที่เกี่ยวข้อง	3	4	4
สรุป	The nonlinear KPSS test extends the classic Kwiatkowski-Phillips-Schmidt-Shin stationarity test by modelling unknown smooth structural breaks in the deterministic trend using a Fourier approximation. Under the null hypothesis the series is stationary around a flexible nonlinear trend, guarding against spurious unit-root findings caused by regime shifts or gradual transitions.	The Augmented Dickey-Fuller (ADF) test is the most widely used test for a unit root — that is, for whether a time series is non-stationary and must be differenced before modelling. Introduced by David Dickey and Wayne Fuller in 1979 and extended by Said and Dickey in 1984 to series with higher-order autocorrelation, it regresses the change in the series on its lagged level plus lagged differences and asks whether the lagged-level coefficient is zero.	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.