This chapter examines the problems of dealing with trending type data when there is uncertainty over whether or not we really have unit roots in the data. This uncertainty is practical – for many macroeconomic and financial variables theory does not imply a unit root in the data however unit...

This paper proposes a version of the DF-GLS test that incorporates up to two breaks in the intercept, namely the DF-GLSTB test. While the asymptotic properties of the DF-GLS test remain valid, the presence of changes in the intercept has an impact on the small sample properties of the test....

This paper considers the problem of testing for structural changes in the trend function of a univariate time series without any prior knowledge as to whether the noise component is stationary or contains an autoregressive unit root. We propose a new approach that builds on the work of Perron...

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...