GAUSS / RATS Codes

UNIT ROOT TESTS

(With or without Structural Breaks)

Disclaimer: This code is provided gratis without any guarantees or warrantees, and it can be used by anyone at the user's discretion.  The codes are believed to be correct but not guaranteed.

Proprietary modifications of this code are not permitted. 

Please contact Junsoo Lee (jlee@cba.ua.edu or www.cba.ua.edu/jlee) if you have any questions.

 


Tests without Structural Breaks

  • ADF TESTS

    ADF Test with fixed lags (adf.txt)

    ADF Test with lags determined from the data (adf.txt)

     

  • Phillips-Perron Tests

    Phillips-Perron Test with fixed truncation lags (needs COINT 2.0)

    Phillips-Perron Test with automatic bandwidth selections (needs COINT 2.0)

     

  • Schmidt-Phillips Tests (Oxford Bulletin, 1992); also including Schmidt-Lee Tests (Economics Letters, 1991)

    Schmidt-Phillips Tests with fixed truncation lags (sp1.txt)

    Schmidt-Phillips Tests with automatic bandwidth selections (needs COINT 2.0)

    Schmidt-Phillips Augmented Test (sp.g)

     

  • KPSS Tests (J. of Econometrics, 1992)

    KPSS Test with fixed truncation lags (kpss.txt) (data: nelplos.dat)

    KPSS Test with automatic bandwidth selections (needs COINT 2.0)

 

Tests with Structural Breaks

    With Given Break Points

  • Perron's (augmented type) Test (Econometrica, 1989) (perron.txt)

     

  • Amsler and Lee's LM (augmented type) Test (Econometric Theory, 1995) (AL.txt)

     

  • Stationarity Test with Multiple Breaks (Editor's book, Lee) (stat.txt)

 

   With Data-dependent Break Points (Gauss)

       (data: gdp.txt  or  gdp.xls)

  • Zivot and Andrews Test (One break) (JBES, 1992) (ZA.txt)

  • Lumsdaine and Papell Test (Two breaks) (Restat, 1997) (LPtwo.txt)

  • Lee and Strazicich LM Test (One break) (LS_One.g)

  • Lee and Strazicich LM Test (Two breaks, Restat, 2003) (LS_two.g)

  • LM Test with Multiple Breaks (multi.txt) (not ready)

With Data-dependent Break Points (RATS)

       (data: gdp.txt  or  gdp.xls)

Note:  The following RATS codes are extended (cloned) from LSunit.src and other codes, which are posted on the Estima web site

     http://www.estima.com/forum/viewtopic.php?t=126

These RATS codes may produce a little different results.  The difference can be minor and negligible in large samples.  In the following codes, the number of discarded initial observations will be smaller as it varies depending on the selected lag value.

 

Tests with a Fourier Non-linear Trend Function

  • LM type Test (Enders and Lee, 2011, forthcoming, Oxford Bulletin)

       PE Example:  LM_four.txt    Data (excel file) 

  • DF Type Test (Enders and Lee, WP)

        PE Example:  unit_four.txt   Data (excel file)  

  • Stationarity Tests (Becker, Enders and Lee, J. of Time Series Analysis, 2006)

      PE Example: stat_four.txt   Data (excel file) 

ADL Threshold Cointegration (with Jing Li) 

  • ADL test (“ADL tests for Threshold Cointegration,” (with Jing Li), forthcoming at Journal of Time Series Analysis) Matlab Code: singleadlbo.m written by Jing.

 

Panel Unit Root Tests

  • Panel LM Unit root Test with Level Shifts (Oxford Bulletin, 2005)

   (data: gdp.txt  or  gdp.xls)

Note:  The Panel LM tests with level shifts are free of the nuisance parameters indicating the break points.  Critical values (Table 1): panelcri.dat  

Source: “Panel LM unit Root Tests with Level Shifts,” (with Kyung So Im and Margie Tieslau), Oxford Bulletin of Economics and Statistics67, 3, 393-419, June 2005.

Note:  In the following codes, both the optimal (heterogeneous) break points and optimal lags are endogenously determined from the data, for each of the cross-section units.  One break (two break) test assumes one break (two breaks) in all cross section units.  

To mitigate the effects of cross-correlations, time fixed effects are allowed as an option.

Note: It may be desirable to allow for different numbers of breaks for different cross-section units.  This may need additional modification of the above codes. 

 

  • Panel LM Unit root Test with Trend Shifts (Working paper; invariant tests, also with cross-correlation corrections)

   (code: to be released soon)

 


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