Hostname: page-component-586b7cd67f-r5fsc Total loading time: 0 Render date: 2024-11-22T04:32:41.011Z Has data issue: false hasContentIssue false

Inference in Time Series Regression When the Order of Integration of a Regressor is Unknown

Published online by Cambridge University Press:  11 February 2009

Graham Elliott
Affiliation:
Harvard University
James H. Stock
Affiliation:
Harvard University

Abstract

The distribution of statistics testing restrictions on the coefficients in time series regressions can depend on the order of integration of the regressors. In practice, the order of integration is rarely known. We examine two conventional approaches to this problem — simply to ignore unit root problems or to use unit root pretests to determine the critical values for second-stage inference—and show that both exhibit substantial size distortions in empirically plausible situations. We then propose an alternative approach in which the second-stage critical values depend continuously on a first-stage statistic that is informative about the order of integration of the regressor. This procedure has the correct size asymptotically and good local asymptotic power.

Type
Articles
Copyright
Copyright © Cambridge University Press 1994

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

1.Andrews, D.W.K.Heteroskedasticity and autocorrelation consistent covariance matrix estimation. Econometrica 59 (1991): 817858.Google Scholar
2.Bobkoski, M.J. Hypothesis Testing in Nonstationary Time Series. Ph.D. Dissertation, University of Wisconsin, 1983.Google Scholar
3.Campbell, J.Y.A variance decomposition for stock returns. Economic Journal 101 (1991): 157179.CrossRefGoogle Scholar
4.Cavanagh, C.Roots Local to Unity. Harvard University, 1985.Google Scholar
5.Chan, N.H.On the parameter inference for nearly nonstationary time series. Journal of the American Statistical Association 83 (1988): 857862.Google Scholar
6.Chan, N.H. & Wei, C.Z.. Asymptotic inference for nearly nonstationary AR(1) processes. Annals of Statistics 15 (1987): 10501063.CrossRefGoogle Scholar
7.Chan, N.H. & Wei, C.Z.. Limiting distributions of least squares estimates of unstable autoregressive processes. Annals of Statistics 16 (1988): 367401.Google Scholar
8.Dickey, D.A. & Fuller, W.A.. Distribution of the estimators for autoregressive time series with a unit root. Journal of the American Statistical Association 74 (1979): 427431.Google Scholar
9.Fama, E.F.Efficient capital markets II. Journal of Finance 46 (1991): 15751617.CrossRefGoogle Scholar
10.Fama, E.F. & French, K.R.. Business conditions and expected returns on stocks and bonds. Journal of Financial Economics 25 (1989): 2349.CrossRefGoogle Scholar
11.Flavin, M.A.The adjustment of consumption to changing expectations about future income. Journal of Political Economy 89 (1981): 9741009.Google Scholar
12.Kwiatkowski, D., Phillips, P.C.B., Schmidt, P. & Shin, Y.. Testing the null hypothesis of stationarity against the alternative of a unit root: How sure are we that economic time series have a unit root? Journal of Econometrics 54 (1992): 159178.CrossRefGoogle Scholar
13.Mankiw, N.G. & Shapiro, M.D.. Trends, random walks and tests of the permanent income hypothesis. Journal of Monetary Economics 16 (1985): 165174.CrossRefGoogle Scholar
14.Nabeya, S. & Tanaka, K.. Asymptotic theory of a test for the constancy of regression coefficients against the random walk alternative. Annals of Statistics 16 (1988): 218235.CrossRefGoogle Scholar
15.Nabeya, S. & Tanaka, K.. A general approach to the limiting distribution for estimators in time series regression with nonstable autoregressive errors. Econometrica 58 (1990): 145163.CrossRefGoogle Scholar
16.Park, J.Y. & Phillips, P.C.B.. Statistical inference in regressions with integrated processes: Part I. Econometric Theory 4 (1988): 468497.CrossRefGoogle Scholar
17.Perron, P.The calculation of the limiting distribution of the least-squares estimator in a near-integrated model. Econometric Theory 5 (1989): 241255.Google Scholar
18.Perron, P.A Test for Changes in a Polynomial Trend Function for a Dynamic Time Series. Princeton University, 1991.Google Scholar
19.Phillips, P.C.B.Understanding spurious regressions in econometrics. Journal of Econometrics 33 (1986): 311340.Google Scholar
20.Phillips, P.C.B.Toward a unified asymptotic theory for autoregression. Biometrika 74 (1987): 535547.Google Scholar
21.Phillips, P.C.B.To criticize the critics: An objective Bayesian analysis of stochastic trends. Journal of Applied Econometrics 6 (1991): 333364.Google Scholar
22.Phillips, P.C.B. Spectral regression for cointegrated time series. In Barnett, W., Powell, J. & Tauchen, G. (eds), Nonparametric and Semiparametric Methods in Econometrics and Statistics, pp. 413436. Cambridge University Press, Cambridge, UK. 1991.Google Scholar
23.Phillips, P.C.B.Optimal inference in cointegrated systems. Econometrica 59 (1991): 283306.CrossRefGoogle Scholar
24.Phillips, P.C.B. & Durlauf, S.N.. Multiple time series regression with integrated processes. Review of Economic Studies 53 (1986): 473496.CrossRefGoogle Scholar
25.Phillips, P.C.B. & Ploberger, W.. Time Series Modeling with a Bayesian Frame of Reference: I. Concepts and Illustrations. Yale University, 1991.Google Scholar
26.Saikkonen, P.Asymptotically efficient estimation of cointegrating regressions. Econometric Theory 1 (1991): 121.CrossRefGoogle Scholar
27.Saikkonen, P. & Luukkonen, R.. Testing for moving average unit root in autoregressive integrated moving average models. Journal of the American Statistical Association 88 (1993): 596601.Google Scholar
28.Sargan, J.D. & Bhargava, A.. Testing for residuals from least squares regression for being generated by the Gaussian random walk. Econometrica 51 (1983): 153174.Google Scholar
29.Sims, CA., Stock, J.H. & Watson, M.W.. Inference in linear time series models with some unit roots. Econometrica 58 (1990): 113144.CrossRefGoogle Scholar
30.Stock, J.H.Deciding between I(1) and I(0). Journal of Econometrics, forthcoming.Google Scholar
31.Stock, J.H. & Watson, M.W.. A simple estimator of cointegrating vectors in higher order integrated systems. Econometrica 61 (1993): 783820.Google Scholar
32.Stock, J.H. & West, K.D.. Integrated regressors and tests of the permanent income hypothesis. Journal of Monetary Economics 21 (1988): 8596.Google Scholar
33.Toda, H.Y. & Phillips, P.C.B.. Vector autoregression and causality. Econometrica 61 (1993): 13671394.Google Scholar