Robust tests for a linear trend with an application to equity indices

In this paper we develop a testing procedure for the presence of a deterministic linear trend in a univariate time series which is robust to whether the series is I(0) or I(1) and requires no knowledge of the form of weak dependence present in the data. Our approach is motivated by the testing proce...

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Main Authors: Astill, Sam, Harvey, David I., Leybourne, Stephen J., Taylor, A.M. Robert
Format: Article
Published: Elsevier 2014
Subjects:
Online Access:https://eprints.nottingham.ac.uk/32665/
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author Astill, Sam
Harvey, David I.
Leybourne, Stephen J.
Taylor, A.M. Robert
author_facet Astill, Sam
Harvey, David I.
Leybourne, Stephen J.
Taylor, A.M. Robert
author_sort Astill, Sam
building Nottingham Research Data Repository
collection Online Access
description In this paper we develop a testing procedure for the presence of a deterministic linear trend in a univariate time series which is robust to whether the series is I(0) or I(1) and requires no knowledge of the form of weak dependence present in the data. Our approach is motivated by the testing procedures of Vogelsang [1998, Econometrica, vol 66, p123–148] and Bunzel and Vogelsang [2005, Journal of Business and Economic Statistics, vol 23, p381–394], but utilises an auxiliary unit root test to switch between critical values in the exact I(1) and I(0) environments, rather than using this unit root test to scale the test statistic as is done in the aforementioned procedures. We show that our proposed tests have uniformly greater local asymptotic power than the tests of Vogelsang (1998) and Bunzel and Vogelsang (2005) when the error process is exact I(1), identical local asymptotic when the error process is I(0), and have better overall local asymptotic power when the error process is near I(1). Our proposed tests also display superior finite sample power to the tests of Vogelsang (1998) and Bunzel and Vogelsang (2005) and are competitive in finite samples with tests designed to be optimal in both the exact I(1) and I(0) environments. We apply our test procedures to a number of equity indices and find that these series appear to have a significant upward deterministic trend, yet are also highly persistent about this long run growth path.
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spelling nottingham-326652020-05-04T16:42:36Z https://eprints.nottingham.ac.uk/32665/ Robust tests for a linear trend with an application to equity indices Astill, Sam Harvey, David I. Leybourne, Stephen J. Taylor, A.M. Robert In this paper we develop a testing procedure for the presence of a deterministic linear trend in a univariate time series which is robust to whether the series is I(0) or I(1) and requires no knowledge of the form of weak dependence present in the data. Our approach is motivated by the testing procedures of Vogelsang [1998, Econometrica, vol 66, p123–148] and Bunzel and Vogelsang [2005, Journal of Business and Economic Statistics, vol 23, p381–394], but utilises an auxiliary unit root test to switch between critical values in the exact I(1) and I(0) environments, rather than using this unit root test to scale the test statistic as is done in the aforementioned procedures. We show that our proposed tests have uniformly greater local asymptotic power than the tests of Vogelsang (1998) and Bunzel and Vogelsang (2005) when the error process is exact I(1), identical local asymptotic when the error process is I(0), and have better overall local asymptotic power when the error process is near I(1). Our proposed tests also display superior finite sample power to the tests of Vogelsang (1998) and Bunzel and Vogelsang (2005) and are competitive in finite samples with tests designed to be optimal in both the exact I(1) and I(0) environments. We apply our test procedures to a number of equity indices and find that these series appear to have a significant upward deterministic trend, yet are also highly persistent about this long run growth path. Elsevier 2014-02-28 Article PeerReviewed Astill, Sam, Harvey, David I., Leybourne, Stephen J. and Taylor, A.M. Robert (2014) Robust tests for a linear trend with an application to equity indices. Journal of Empirical Finance, 29 . pp. 168-185. ISSN 1879-1727 Linear trend; Unit root tests; Strong serial correlation http://www.sciencedirect.com/science/article/pii/S0927539814000206 doi:10.1016/j.jempfin.2014.02.004 doi:10.1016/j.jempfin.2014.02.004
spellingShingle Linear trend; Unit root tests; Strong serial correlation
Astill, Sam
Harvey, David I.
Leybourne, Stephen J.
Taylor, A.M. Robert
Robust tests for a linear trend with an application to equity indices
title Robust tests for a linear trend with an application to equity indices
title_full Robust tests for a linear trend with an application to equity indices
title_fullStr Robust tests for a linear trend with an application to equity indices
title_full_unstemmed Robust tests for a linear trend with an application to equity indices
title_short Robust tests for a linear trend with an application to equity indices
title_sort robust tests for a linear trend with an application to equity indices
topic Linear trend; Unit root tests; Strong serial correlation
url https://eprints.nottingham.ac.uk/32665/
https://eprints.nottingham.ac.uk/32665/
https://eprints.nottingham.ac.uk/32665/