Abstract
Ng and Perron (Econometrica 69:1519–1554, 2001) demonstrated the merits to employing their Modified Akaike Information Criterion to select the optimal lag length in the Elliott, Rothenberg and Stock (Econometrica 64:813–836, 1996) unit rot test. Perron and Qu (Econ Lett 84:12–19, 2007) introduced an empirical method that resolved an associated power problem for non-local alternatives. While Cheung and Lai (Oxford Bull Econ Stat 57:411-419, 1995) contains response surface estimates to generate finite-sample, lag-adjusted critical five and ten percent values for use in applied work, these relate to the original Elliott et al. (Econometrica 64:813–836, 1996) test. This paper provides response surfaces estimates of critical values for both the Ng and Perron (Econometrica 69:1519–1554, 2001) and Perron and Qu (Econ Lett 84:12–19, 2007) approaches, demonstrating they are sometimes quite different, an important consideration when performing inference.
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Data and Computer Code Availability
Matlab programs to replicate the analysis and calculate finite sample lag adjusted critical values and probability values are available as electronic supplementary material and also at http://web.business.queensu.ca/faculty/psephton under MatlabFiles (ADFGLS2020.zip) and on request to the author (Peter.Sephton@queensu.ca).
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References
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Sephton, P.S. Finite Sample Lag Adjusted Critical Values of the ADF-GLS Test. Comput Econ 59, 177–183 (2022). https://doi.org/10.1007/s10614-020-10082-6
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DOI: https://doi.org/10.1007/s10614-020-10082-6