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Cowles Foundation Discussion Papers

2002

Long memory

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Full-Text Articles in Social and Behavioral Sciences

Adaptive Local Polynomial Whittle Estimation Of Long-Range Dependence, Donald W.K. Andrews, Yixiao Sun Oct 2002

Adaptive Local Polynomial Whittle Estimation Of Long-Range Dependence, Donald W.K. Andrews, Yixiao Sun

Cowles Foundation Discussion Papers

The local Whittle (or Gaussian semiparametric) estimator of long range dependence, proposed by Künsch (1987) and analyzed by Robinson (1995a), has a relatively slow rate of convergence and a finite sample bias that can be large. In this paper, we generalize the local Whittle estimator to circumvent these problems. Instead of approximating the short-run component of the spectrum, φ(λ), by a constant in a shrinking neighborhood of frequency zero, we approximate its logarithm by a polynomial. This leads to a “local polynomial Whittle” (LPW) estimator. We specify a data-dependent adaptive procedure that adjusts the degree of the polynomial to the …


Higher-Order Improvements Of The Parametric Bootstrap For Long-Memory Gaussian Processes, Donald W.K. Andrews, Offer Lieberman Aug 2002

Higher-Order Improvements Of The Parametric Bootstrap For Long-Memory Gaussian Processes, Donald W.K. Andrews, Offer Lieberman

Cowles Foundation Discussion Papers

This paper determines coverage probability errors of both delta method and parametric bootstrap confidence intervals (CIs) for the covariance parameters of stationary long-memory Gaussian time series. CIs for the long-memory parameter d 0 are included. The results establish that the bootstrap provides higher-order improvements over the delta method. Analogous results are given for tests. The CIs and tests are based on one or other of two approximate maximum likelihood estimators. The first estimator solves the first-order conditions with respect to the covariance parameters of a “plug-in” log-likelihood function that has the unknown mean replaced by the sample mean. The second …


Error Bounds And Asymptotic Expansions For Toeplitz Product Functionals Of Unbounded Spectra, Offer Lieberman, Peter C.B. Phillips Jun 2002

Error Bounds And Asymptotic Expansions For Toeplitz Product Functionals Of Unbounded Spectra, Offer Lieberman, Peter C.B. Phillips

Cowles Foundation Discussion Papers

This paper establishes error orders for integral limit approximations to traces of powers to the p th order) of products of Toeplitz matrices. Such products arise frequently in the analysis of stationary time series and in the development of asymptotic expansions. The elements of the matrices are Fourier transforms of functions which we allow to be bounded, unbounded, or even to vanish on [- π,π ], thereby including important cases such as the spectral functions of fractional processes. Error rates are also given in the case in which the matrix product involves inverse matrices. The rates are sharp up to …


Local Whittle Estimation Of Fractional Integration, Katsumi Shimotsu, Peter C.B. Phillips May 2002

Local Whittle Estimation Of Fractional Integration, Katsumi Shimotsu, Peter C.B. Phillips

Cowles Foundation Discussion Papers

An exact form of the local Whittle likelihood is studied with the intent of developing a general purpose estimation procedure for the memory parameter ( d ) that does not rely on tapering or differencing prefilters. The resulting exact local Whittle estimator is shown to be consistent and to have the same N (0,1/4) limit distribution for all values of d if the optimization covers an interval of width less than 9/2 and the initial value of the process is known.