This paper uses Monte Carlo simulations to analyze the performance of several seasonal unit root tests for monthly time series. The tests are those of Dickey, Hasza and Fuller (DHF), Hylleberg, Engle, Granger and Yoo (HEGY), and Osborn, Chui, Smith and Birchenhall (OCSB). The unit root test of...

In this paper we introduce a sequential seasonal unit root testing approach which explicitly addresses its application to high frequency data. The main idea is to see which unit roots at higher frequency data can also be found in temporally aggregated data. We illustrate our procedure to the...

Self-Exciting Threshold Autoregressive (SETAR) models are a non-linear variant of conventional linear Autoregressive (AR) models. One advantage of SETAR models over conventional AR models lies in its flexible nature in dealing with possible asymmetric behaviour of economic variables. The concept...