Regression model

Augmented Dickey-Fuller (ADF) Unit-Root Test

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.

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Sources

  1. 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. DOI: 10.1080/01621459.1979.10482531
  2. Said, S. E., & Dickey, D. A. (1984). Testing for unit roots in autoregressive-moving average models of unknown order. Biometrika, 71(3), 599–607. DOI: 10.1093/biomet/71.3.599

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Referenced by

ScholarGateAugmented Dickey-Fuller Test (Augmented Dickey-Fuller (ADF) Unit-Root Test). Retrieved 2026-06-04 from https://scholargate.app/en/econometrics/adf-test