Manuel Artís Ortuño

Unit root and stationarity tests’ wedding

Abstract In this paper the joint confirmation hypothesis (JCH) of unit root for the simultaneous use of the DF and KPSS tests, on the one hand, and the PP and KPSS tests, on the other, is studied. Critical values to be applied when testing this confirmation hypothesis are computed. The performance of this approach is analysed through a Monte Carlo experiment which shows that the use of these critical values produces a better characterization of the DGP when there is a unit root.

Response surfaces estimates for the Dickey-Fuller unit root test with structural breaks

Abstract The lack of suitable critical values for the Dickey-Fuller integrability test in finite-samples can drive researchers to spurious conclusions when using asymptotic critical values. In this paper we estimate response surfaces for the Dickey-Fuller unit root test with structural breaks that allow us to obtain approximate critical values for any sample size and break date.