Repository logo
 

Testing against changing correlation


Change log

Authors

Harvey, A 
Thiele, S 

Abstract

A test for time-varying correlation is developed within the framework of a dynamic conditional score (DCS) model for both Gaussian and Student t-distributions. The test may be interpreted as a Lagrange multiplier test and modified to allow for the estimation of models for time-varying volatility in the individual series. Unlike standard moment-based tests, the score-based test statistic includes information on the level of correlation under the null hypothesis and local power arguments indicate the benefits of doing so. A simulation study shows that the performance of the score-based test is strong relative to existing tests across a range of data generating processes. An application to the Hong Kong and South Korean equity markets shows that the new test reveals changes in correlation that are not detected by the standard moment-based test.

Description

Keywords

Dynamic conditional score, EGARCH Lagrange multiplier test, Portmanteau test, Time-varying covariance matrices

Journal Title

Journal of Empirical Finance

Conference Name

Journal ISSN

0927-5398
1879-1727

Volume Title

38

Publisher

Elsevier BV
Sponsorship
Some of the results in this paper were presented at the Time Series Workshop at the University of La Laguna, Tenerife, in January 2014 and at the Econometric Society Australasian meeting in Hobart in July, 2014. We would like to thank participants, particularly Yoosoon Chang, for helpful comments. Thanks also to Jukka Nyblom, our colleagues at Cambridge and two referees. We are grateful to the Keynes Fund for financial support. Simulations were run on the CamGrid cluster at the University of Cambridge.