Regression modelEconometrics / time series

Nonlinear KPSS Test

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.

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Sources

  1. 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. DOI: 10.1111/j.1467-9892.2006.00478.x
  2. Enders, W., & Lee, J. (2012). A unit root test using a Fourier series to approximate smooth breaks. Oxford Bulletin of Economics and Statistics, 74(4), 574-599. DOI: 10.1111/j.1468-0084.2011.00662.x

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Referenced by

ScholarGateNonlinear KPSS Test (Nonlinear Kwiatkowski-Phillips-Schmidt-Shin Test). Retrieved 2026-06-04 from https://scholargate.app/en/econometrics/nonlinear-kpss-test