This paper studies the behaviour of the HEGY tests for quarterly data, for seasonal autoregressive unit roots, when the time series being analysed is deterministic seasonal stationary but exhibits a change in the seasonal pattern. As a by-product, we also analyse the HEGY tests for the...

Nonparametric unit-root tests are a useful addendum to the tool-box of time-series analysis. They tend to trade off power for enhanced robustness features. We consider combinations of the RURS (seasonal range unit roots) test statistic and a variant of the level-crossings count. This combination...

In this paper we propose tests based on GLS-detrending for testing the null hypothesis of deterministic seasonality. Unlike existing tests for deterministic seasonality, our tests do not suff er from asymptotic size distortions under near integration. We also investigate the behavior of the...