Abstract
Economic and financial time series have frequently been successfully modelled by autoregressive moving-average (ARMA) schemes of the type, where ε t is an orthogonal sequence (that is,E(ε t ) = 0, E(ε t ε1 s ) = 0 for all t ≠ s), L is the backshift operator for which Ly t = yt − 1 and a(L) b(L) are finite-order lag polynomials, whose leading coefficients are a0 = b0 = 1. Parsimonious schemes (often with p + q ≤ 3) are usually selected in practice either by informal ‘model identification’ processes such as those described in the text by Box and Jenkins (1976) or more formal order-selection criteria which penalize choices of large p and/or q. Model (1) is assumed to be irreducible, so that a(L) and b(L) have no common factors. The model (1) and the time series y t are said to have an autoregressive unit root if a(L) factors as (1 − L)a1(L) and a moving-average unit root if b(L) factors as (1 − L)a1(L)
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Bibliography
Andrews, D.W.K. 1993. Exactly median-unbiased estimation of first-order autoregressive/unit root models. Econometrica 61, 139–66.
Andrews, D.W.K. and Guggenberger, P. 2006. Asymptotics for stationary very nearly unit root processes. Mimeo, Yale University.
Bai, J. 1997. Estimating multiple break one at a time. Econometric Theory 13, 315–52.
Bai, L. and Perron, P. 1998. Estimating and testing linear models with multiple structural changes. Econometrica 66, 47–78.
Bai, L. and Perron, P. 2006. Multiple structural change models: a simulation analysis. In Econometric Theory and Practice, ed. Corbae, B.E. Hansen and S.N. Durlauf. New York: Cambridge University Press.
Baltagi, B.H. and Kao, C. 2000. Nonstationary panels, cointegration in panels and dynamic panels: a survey. Advances in Econometrics 15, 7–51.
Banerjee, A., Lumsdaine, R. and Stock, J. 1992. Recursive and sequential tests of the unit root and trend break hypotheses: theory and international evidence. Journal of Business and Economic Statistics 10, 271–87.
Beare, B.K. 2006. Unit root testing with unstable volatility. Mimeo, Yale University.
Berkes, I. and Horváth, L. 2006. Convergence of integral functionals of stochastic processes. Econometric Theory 22, 304–22.
Beveridge, S. and Nelson, C.R. 1981. A new approach to decomposition of economic time series into permanent and transitory components with particular attention to measurement of the ‘business cycle’. Journal of Monetary Economics 7, 151–74.
Bhargava, A. 1986. On the theory of testing for unit roots in observed time series. Review of Economic Studies 52, 369–84.
Box, G.E.P. and Jenkins, G.M. 1976. Time Series Analysis: Forecasting and Control, rev. edn. San Francisco: Holden Day.
Byrne, J.P. and Perman, R. 2006. Unit roots and structural breaks: a survey of the literature. Mimeo, University of Strathclyde.
Campbell, J.Y. and Perron, P. 1991. Pitfalls and opportunities: what macroeconomists should know about unit roots (with discussion). In NBER Macroeconomics Annual 1991, ed. O.J. Blanchard and S. Fischer. Cambridge, MA: MIT Press.
Campbell, J.Y. and Shiller, R.J. 1988. Interpreting cointegrated models. Journal of Economic Dynamics and Control 12, 505–22.
Cavaliere, G. 2004. Unit root tests under time-varying variances. Econometric Reviews 23, 259–92.
Cavaliere, G. and Taylor, A.M.R. 2007. Testing for unit roots in time series models with non-stationary volatility. Journal of Econometrics 140(2), 919–47.
Chan, N.H. and Wei, C.Z. 1987. Asymptotic inference for nearly nonstationary AR(1) processes. Annals of Statistics 15, 1050–63.
Chan, N.H. and Wei, C.Z. 1988. Limiting distributions of least squares estimates of unstable autoregressive processes. Annals of Statistics 16, 367–401.
Choi, I. 2001. Unit roots for panel data. Journal of International Money and Finance 20, 249–72.
Choi, I. and Phillips, P.C.B. 1993. Testing for a unit root by frequency domain regression. Journal of Econometrics 59, 263–86.
Christiano, L.J. 1992. Searching for a break in GNP. Journal of Business & Economic Statistics 10, 237–50.
de Jong, R. 2004. Addendum to ‘asymptotics for nonlinear transformations of integrated time series’. Econometric Theory 20, 623–35.
Dejong, D.N. and Whiteman, C.H. 1991a. Reconsidering trends and random walks in macroeconomic time series. Journal of Monetary Economics 28, 221–54.
Dejong, D.N. and Whiteman, C.H. 1991b. The temporal stability of dividends and stock prices: evidence from the likelihood function. American Economic Review 81, 600–17.
Dickey, D.A. 1976. Estimation and hypothesis testing in nonstationary time series. Ph.D. thesis, Iowa State University.
Dickey, D.A. and Fuller, W.A. 1979. Distribution of the estimators for autoregressive time series with a unit root. Journal of the American Statistical Association 74, 427–31.
Dickey, D.A. and Fuller, W.A. 1981. Likelihood ratio statistics for autoregressive time series with a unit root. Econometrica 49, 1057–72.
Diebold, F.X. and Nerlove, M. 1990. Unit roots in economic time series. Advances in Econometrics 8, 3–70.
Dolado, J.J., Jenkinson, T. and Sosvilla-Rivero, S. 1990. Cointegration and unit roots. Journal of Economic Surveys 4, 249–73.
Duffie, D. 1988. Security Markets: Stochastic Models. San Diego: Academic Press.
Elliott, G., Rothenberg, T.J. and Stock, J.H. 1995. Efficient tests of an autoregressive unit root. Econometrica 64, 813–36.
Engle, R.F. and Bollerslev, T. 1986. Modeling the persistence of conditional variances. Econometric Reviews 5, 1–50.
Engle, R.F. and Granger, C.W.J. 1987. Co-integration and error correction: representation, estimation, and testing. Econometrica 55, 251–76.
Evans, G.B.A. and Savin, N.E. 1981. Testing for unit roots: 1. Econometrica 49, 753–79.
Evans, G.B.A. and Savin, N.E. 1984. Testing for unit roots: 2. Econometrica 52, 1241–69.
Fuller, W.A. 1976. Introduction of Statistical Time Series. New York: Wiley.
Ghysels, E. and Osborn, D.R. 2001. Econometric Analysis of Seasonal Time Series. Cambridge: Cambridge University Press.
Giraitis, L. and Phillips, P.C.B. 2006. Uniform limit theory for stationary autoregression. Journal of Time Series Analysis 27, 51–60.
Gouriéroux, C, Renault, E. and Touzi, N. 2000. Calibration by simulation for small sample bias correction. In Simulation-Based Inference in Econometrics: Methods and Applications, ed. R.S. Mariano, T. Schuermann and M. Weeks. Cambridge: Cambridge University Press.
Gouriéroux, C, Phillips, P.C.B. and Yu, J. 2006. Indirect inference for dynamic panel models. Discussion Paper No. 1550, Cowles Foundation, Yale University.
Hall, R.E. 1978. Stochastic implications of the life cycle-permanent income hypothesis. Journal of Political Economy 86, 971–87.
Hall, A. 1989. Testing for a unit root in the presence of moving average errors. Biometrika 76, 49–56.
Hall, P. and Heyde, C.C. 1980. Martingale Limit Theory and its Application. New York: Academic Press.
Harris, D., Leybourne, S. and McCabe, B. 2007. Modified KPSS tests for near integration. Econometric Theory 23, 355–63.
Hlouskova, J. and Wagner, M. 2006. The performance of panel unit root and stationarity tests: results from a large scale simulation study. Econometric Reviews 25, 85–116.
Hong, S.H. and Phillips, P.C.B. 2005. Testing linearity in cointegrating relations with an application to purchasing power parity. Discussion Paper No. 1541, Cowles Foundation, Yale University.
Hu, L. and Phillips, P.C.B. 2004. Dynamics of the federal funds target rate: a nonstationary discrete choice approach. Journal of Applied Econometrics 19, 851–67.
Hylleberg, S., Engle, R.F., Granger, C.W.J. and Yoo, S. 1990. Seasonal integration and cointegration. Journal of Econometrics 44, 215–38.
Ibragimov, R. and Phillips, P.C.B. 2004. Regression asymptotics using martingale convergence methods. Discussion Paper No. 1473, Cowles Foundation, Yale University.
Johansen, S. 1988. Statistical analysis of cointegration vectors. Journal of Economic Dynamics and Control 12, 231–54.
Kapetanios, G. 2005. Unit root testing against the alternative hypothesis of up to m structural breaks. Journal of Time Series Analysis 26, 123–33.
Karlsen, H.A., Myklebust, T and Tjøstheim, D. 2007. Nonparametric estimation in a nonlinear cointegration model. Annals of Statistics 35(1).
Kasparis, I. 2004. Detection of functional form misspecification in cointegrating relations. Mimeo, University of Nottingham.
Kim, J.Y. 1994. Bayesian asymptotic theory in a time series model with a possible nonstationary process. Econometric Theory 10, 764–73.
Kwiatkowski, D., Phillips, P.C.B., Schmidt, P. and Shin, Y 1992. Testing the null 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, 159–78.
Lee, C.C. and Phillips, P.C.B. 1994. An ARMA prewhitened long-run variance estimator. Mimeo, Yale University.
Lee, J.S. 1996. On the power of stationary tests using optimal bandwidth estimates. Economics Letters 51, 131–7.
Leeb, H. and Potscher, B. 2001. The variance of an integrated process need not diverge to infinity and related results on partial sums of stationary processes. Econometric Theory 17, 671–85.
MacKinnon, J.G. 1994. Approximate asymptotic distribution functions for unit-root and cointegration tests. Journal of Business and Economic Statistics 12, 167–76.
Müller, U. 2005. Size and power of tests for stationarity in highly autocorrelated time series. Journal of Econometrics 128, 195–213.
Müller, U. and Elliott, G. 2003. Tests for unit roots and the initial condition. Econometrica 71, 1269–86.
Nelson, D.B. 1990. Stationarity and persistence in the GARCH (1, 1) model. Econometric Theory 6, 318–34.
Nelson, C.R. and Plosser, C. 1982. Trends and random walks in macroeconomic time series: some evidence and implications. Journal of Monetary Econometrics 10, 139–62.
Ng, S. and Perron, P. 1995. Unit root tests in ARMA models with data dependent methods for the selection of the truncation lag. Journal of the American Statistical Association 90, 268–81.
Ng, S. and Perron, P. 2001. Lag length selection and the construction of unit root tests with good size and power. Econometrica 69, 1519–54.
Ouliaris, S., Park, J.Y. and Phillips, P.C.B. 1989. Testing for a unit root in the presence of a maintained trend. In Advances in Econometrics and Modelling, ed. B. Raj. Norwell, MA: Kluwer.
Park, J.Y. 1990. Testing for unit roots and cointegration by variable addition. Advances in Econometrics 8, 107–33.
Park, J.Y. and Phillips, P.C.B. 1988. Statistical inference in regressions with integrated processes: Part I. Econometric Theory 4, 468–97.
Park, J.Y. and Phillips, P.C.B. 1989. Statistical inference in regressions with integrated processes: Part II. Econometric Theory 5, 95–131.
Park, J.Y. and Phillips, P.C.B. 1999. Asymptotics for nonlinear transformations of integrated time series. Econometric Theory 15, 269–98.
Park, J.Y. and Phillips, P.C.B. 2000. Nonstationary binary choice. Econometrica 68, 1249–80.
Park, J.Y. and Phillips, P.C.B. 2001. Nonlinear regressions with integrated time series. Econometrica 69, 1452–98.
Park, J.Y. and Sung, J. 1994. Testing for unit roots in models with structural change. Econometric Theory 10, 917–36.
Perron, P. 1989. The great crash, the oil price shock and the unit root hypothesis. Econometrica 57, 1361–401.
Phillips, P.C.B. 1986. Understanding spurious regressions in econometrics. Journal of Econometrics 33, 311–10.
Phillips, P.C.B. 1987a. Time series regression with a unit root. Econometrica 55, 277–301.
Phillips, P.C.B. 1987b. Towards a unified asymptotic theory of autoregression. Biometrika 74, 535–47.
Phillips, P.C.B. 1988a. Regression theory for near-integrated time series. Econometrica 56, 1021–44.
Phillips, P.C.B. 1988b. Multiple regression with integrated processes. In Statistical Inference from Stochastic Processes, ed. N.U. Prabhu. Contemporary Mathematics 80, 79–106.
Phillips, P.C.B. 1991a. To criticize the critics: an objective Bayesian analysis of stochastic trends. Journal of Applied Econometrics 6, 333–64.
Phillips, P.C.B. 1991b. Bayesian routes and unit roots: de rebus prioribus semper est disputandum. Journal of Applied Econometrics 6, 435–74.
Phillips, P.C.B. 1992. The long-run Australian consumption function reexamined: an empirical exercise in Bayesian inference. In Long Run Equilibrium and Macroeconomic Modelling, ed. C. Hargreaves. Cheltenham: Edward Elgar.
Phillips, P.C.B. 1994. Model determination and macroeconomic activity. Fisher-Schultz Lecture to the European Meetings of the Econometric Society, Maastricht. Discussion Paper No. 1083, Cowles Foundation, Yale University.
Phillips, P.C.B. 1995. Bayesian model selection and prediction with empirical applications. Journal of Econometrics 69, 289–332.
Phillips, P.C.B. 1996. Econometric model determination. Econometrica 64, 763–812.
Phillips, P.C.B. 1998. New tools for understanding spurious regressions. Econometrica 66, 1299–326.
Phillips, P.C.B. 2001. New unit root asymptotics in the presence of deterministic trends. Journal of Econometrics 11, 323–53.
Phillips, P.C.B. 2006. When the tail wags the unit root limit distribution. Mimeo, Yale University.
Phillips, P.C.B. and Durlauf, S.N. 1986. Multiple time series regression with integrated processes. Review of Economic Studies 53, 473–96.
Phillips, P.C.B. and Han, C. 2007. Gaussian inference in AR(1) time series with or without a unit root. Econometric Theory 24(3).
Phillips, P.C.B. and Hansen, B.E. 1990. Statistical inference in instrumental variables regression with I(1) processes. Review of Economic Studies 57, 99–125.
Phillips, P.C.B. and Magdalinos, T. 2007. Limit theory for moderate deviations from a unit root. Journal of Econometrics 136, 115–30.
Phillips, P.C.B. and Moon, H.R. 1999. Linear regression limit theory for nonstationary panel data. Econometrica 67, 1057–111.
Phillips, P.C.B. and Moon, H.R. 2000. Nonstationary panel data analysis: an overview of some recent developments. Econometric Reviews 19, 263–86.
Phillips, P.C.B. and Ouliaris, S. 1990. Asymptotic properties of residual based tests for cointegration. Econometrica 58, 165–93.
Phillips, P.C.B., Park, J.Y. and Chang, Y. 2004. Nonlinear instrumental variable estimation of an autoregression. Journal of Econometrics 118, 219–46.
Phillips, P.C.B. and Perron, P. 1988. Testing for a unit root in time series regression. Biometrika 75, 335–46.
Phillips, P.C.B. and Ploberger, W. 1994. Posterior odds testing for a unit root with data-based model selection. Econometric Theory 10, 774–808.
Phillips, P.C.B. and Ploberger, W. 1996. An asymptotic theory of Bayesian inference for time series. Econometrica 64, 381–113.
Phillips, P.C.B. and Solo, V. 1992. Asymptotics for linear processes. Annals of Statistics 20, 971–1001.
Phillips, P.C.B. and Xiao, Z. 1998. A primer on unit root testing. Journal of Economic Surveys 12, 423–69.
Ploberger, W. 2004. A complete class of tests when the likelihood is locally asymptotically quadratic. Journal of Econometrics 118, 67–94.
Pötscher, B.M. 2004. Nonlinear functions and convergence to Brownian motion: beyond the continuous mapping theorem. Econometric Theory 20, 1–22.
Robinson, P.M. 1995. Gaussian semiparametric estimation of long range dependence. Annals of Statistics 23, 1630–61.
Said, S.E. and Dickey, D.A. 1984. Testing for unit roots in autoregressive moving average models of unknown order. Biometrika 71, 599–608.
Sargan, J.D. and Bhargava, A. 1983. Testing residuals from least squares regression for being generated by the Gaussian random walk. Econometrica 51, 153–74.
Schmidt, P. and Phillips, P.C.B. 1992. LM tests for a unit root in the presence of deterministic trends. Oxford Bulletin of Economics and Statistics 54, 257–87.
Shimotsu, K. and Phillips, P.C.B. 2005. Exact local whittle estimation of fractional integration. Annals of Statistics 33, 1890–933.
Schotman, P. and van Dijk, H.K. 1991. A Bayesian analysis of the unit root in real exchange rates. Journal of Econometrics 49, 195–238.
Sims, C.A. and Uhlig, H. 1991. Understanding unit rooters: a helicopter tour. Econometrica 59, 1591–9.
So, B.S. and Shin, D.W. 1999. Cauchy estimators for autoregressive processes with applications to unit root tests and confidence intervals. Econometric Theory 15, 165–76.
Solo, V. 1984. The order of differencing in ARIMA models. Journal of the American Statistical Association 79, 916–21.
Stock, J.H. 1991. Confidence intervals for the largest autoregressive root in US macroeconomic time series. Journal of Monetary Economics 28, 435–59.
Stock, J. 1994a. Deciding between I(1) and I(0). Journal of Econometrics 63, 105–31.
Stock, J.H. 1994b. Unit roots, structural breaks and trends. In Handbook of Econometrics, vol. 4, ed. R.F. Engle and D. McFadden. Amsterdam: North-Holland.
Stock, J.H. 1999. A class of tests for integration and cointegration. In Cointegration, Causality and Forecasting: A Festschrift in Honour of Clive W. J. Granger, ed. R.F. Engle and H. White. Oxford: Oxford University Press.
Stock, J.H. and Watson, M.W. 1988. Variable trends in economic time series. Journal of Economic Perspectives 2(3), 147–74.
Sul, D., Phillips, P.C.B. and Choi, C.-Y. 2006. Prewhitening bias in HAC estimation. Oxford Bulletin of Economics and Statistics 67, 517–46.
Wang, Q. and Phillips, P.C.B. 2006. Asymptotic theory for local time density estimation and nonparametric cointegrating regression. Discussion Paper no. 1594, Cowles Foundation, Yale University.
Wei, C.Z. 1992. On predictive least squares principles. Annals of Statistics 20, 1–42.
Xiao, Z. and Phillips, P.C.B. 1998. An ADF coefficient test for a unit root in ARMA models of unknown order with empirical applications to the U.S. economy. Econometrics Journal 1, 27–43.
Zivot, E. and Andrews, D.W.K. 1992. Further evidence on the great crash, the oil price shock and the unit root hypothesis. Journal of Business and Economic Statistics 10, 251–70.
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Phillips, P.C.B. (2010). Unit Roots. In: Durlauf, S.N., Blume, L.E. (eds) Macroeconometrics and Time Series Analysis. The New Palgrave Economics Collection. Palgrave Macmillan, London. https://doi.org/10.1057/9780230280830_37
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