Hostname: page-component-8448b6f56d-m8qmq Total loading time: 0 Render date: 2024-04-24T01:38:39.424Z Has data issue: false hasContentIssue false

REGRESSION-BASED SEASONAL UNIT ROOT TESTS

Published online by Cambridge University Press:  01 April 2009

Richard J. Smith
Affiliation:
University of Cambridge
A.M. Robert Taylor*
Affiliation:
University of Nottingham
Tomas del Barrio Castro
Affiliation:
Universitat de les Illes Balears
*
*Address correspondence to Robert Taylor, Granger Centre for Time Series Econometrics, School of Economics, The Sir Clive Granger Building, University of Nottingham, Nottingham NG7 2RD, United Kingdom; e-mail: Robert. Taylor@nottingham.ac.uk.

Abstract

The contribution of this paper is threefold. First, a characterization theorem of the subhypotheses comprising the seasonal unit root hypothesis is presented that provides a precise formulation of the alternative hypotheses associated with regression- based seasonal unit root tests. Second, it proposes regression-based tests for the seasonal unit root hypothesis that allow a general seasonal aspect for the data and are similar both exactly and asymptotically with respect to initial values and seasonal drift parameters. Third, limiting distribution theory is given for these statistics where, in contrast to previous papers in the literature, in doing so it is not assumed that unit roots hold at all of the zero and seasonal frequencies. This is shown to alter the large-sample null distribution theory for regression t-statistics for unit roots at the complex frequencies, but interestingly to not affect the limiting null distributions of the regression t-statistics for unit roots at the zero and Nyquist frequencies and regression F-statistics for unit roots at the complex frequencies. Our results therefore have important implications for how tests of the seasonal unit root hypothesis should be conducted in practice. Associated simulation evidence on the size and power properties of the statistics presented in this paper is given that is consonant with the predictions from the large-sample theory.

Type
ARTICLES
Copyright
Copyright © Cambridge University Press 2009

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Beaulieu, J.J. & Miron, J.A. (1992) Seasonal Unit Roots in Aggregate U.S. Data. National Bureau of Economic Research Technical Working Paper 126.Google Scholar
Beaulieu, J.J. & Miron, J.A. (1993) Seasonal unit roots in aggregate U.S. data. Journal of Econometrics 55, 305–328.CrossRefGoogle Scholar
Boswijk, H.P. & Franses, P.H. (1996) Unit roots in periodic autoregressions. Journal of Time Series Analysis 17, 221–245.CrossRefGoogle Scholar
Burridge, P. & Taylor, A.M.R. (2001) On the properties of regression-based tests for seasonal unit roots in the presence of higher-order serial correlation. Journal of Business & Economic Statistics 19, 374–379.CrossRefGoogle Scholar
Burridge, P. & Taylor, A.M.R. (2004) Bootstrapping the HEGY seasonal unit root tests. Journal of Econometrics 123, 67–87.CrossRefGoogle Scholar
Canova, F. & Hansen, B.E. (1995) Are seasonal patterns constant over time? A test for seasonal stability. Journal of Business & Economic Statistics 13, 237–252.Google Scholar
Davis, P.J. (1979) Circulant Matrices. Wiley-Interscience.Google Scholar
Engle, R.F. & Granger, C.W.J. (1987) Co-integration and error correction: Representation, estimation and testing. Journal of Econometrics 55, 251–276.CrossRefGoogle Scholar
Engle, R.F., Granger, C.W.J., Hylleberg, S., & Lee, H.S. (1993) Seasonal cointegration: The Japanese consumption function. Journal of Econometrics 55, 275–298.CrossRefGoogle Scholar
Franses, P.H. (1994) A multivariate approach to modelling univariate seasonal time series. Journal of Econometrics 63, 133–151.Google Scholar
Fuller, W.A. (1996) Introduction to Statistical Time Series, 2nd ed. Wiley.Google Scholar
Ghysels, E., Lee, H.S., & Noh, J. (1994) Testing for unit roots in seasonal time series: Some theoretical extensions and a Monte Carlo investigation. Journal of Econometrics 62, 415–442.Google Scholar
Ghysels, E. & Osborn, D.R. (2005) The Econometric Analysis of Seasonal Time Series. Cambridge University Press.Google Scholar
Gray, R.M. (2005) Toeplitz and Circulant Matrices. A Review. Now Publishers.Google Scholar
Hylleberg, S., Engle, R.F., Granger, C.W.J., & Yoo, B.S. (1990) Seasonal integration and cointegration. Journal of Econometrics 44, 215–238.CrossRefGoogle Scholar
Rodrigues, P.M.M. & Taylor, A.M.R. (2004) Asymptotic distributions for regression-based seasonal unit root test statistics in a near-integrated model. Econometric Theory 20, 645–670.Google Scholar
Smith, R.J. & Taylor, A.M.R. (1998) Additional critical values and asymptotic representations for seasonal unit root tests. Journal of Econometrics 85, 269–288.Google Scholar
Smith, R.J. & Taylor, A.M.R. (1999) Likelihood ratio tests for seasonal unit roots. Journal of Time Series Analysis 20, 453–476.Google Scholar
Taylor, A.M.R. (1998) Testing for unit roots in monthly time series. Journal of Time Series Analysis 19, 349–368.Google Scholar
Taylor, A.M.R. (2003) Robust stationarity testing in seasonal time series processes. Journal of Business & Economic Statistics 21, 156–163.Google Scholar