Leybourne et al. (J. Econom. 87 (1998) 191) have shown the Dickey-Fuller (J. Amer. Statist. Assoc. 74 (1979) 427) unit root test to suffer from severe oversizing in the presence of level breaks. In this paper it is shown that recursive mean adjustment can correct this distortion, even for large...

The properties of modified Dickey-Fuller tests are examined when applied to momentum threshold autoregressive processes. The tests are found to possess high power, outperforming the standard Dickey-Fuller test and even the asymmetric momentum threshold autoregressive unit root test. The results...

Recent research has shown the momentum-threshold autoregressive (MTAR) unit root test of Enders and Granger (J. Business Econom. Statist. 16 (1998) 304) to exhibit less power than modified Dickey-Fuller tests when applied to MTAR processes. In this paper a revised MTAR test is proposed which...

The finite-sample properties of cointegration tests incorporating structural change are derived when applied to independent unit root processes subject to changes in innovation variance. It is shown that decreases in innovation variance can result in severe size distortion, with the extent of...

The finite-sample size properties of smooth transition unit root tests are examined when applied to unit root processes subject to breaks in either level or drift. In contrast to the weighted symmetric and recursively mean-adjusted unit root tests which have been shown to be robust in these...