Published online by Cambridge University Press: 18 June 2020
While Perron and Wada (2009) maximum likelihood estimation approach suggests that postwar US real GDP follows a trend stationary process (TSP), our Bayesian approach based on the same model and the same sample suggests that it follows a difference stationary process (DSP). We first show that the results based on the approach should be interpreted with caution, as they are relatively more subject to the ‘pile-up problem’ than those based on the Bayesian approach. We then directly estimate and compare the two competing TSP and DSP models of real GDP within the Bayesian framework. Our empirical results suggest that a DSP model is preferred to a TSP model both in terms of in-sample fits and out-of-sample forecasts.
An earlier version of this article has been included as Chapter 1 of Jaeho Kim's Ph.D. dissertation at the University of Washington. Chang-Jin Kim acknowledges financial support from the Bryan C. Cressey Professorship at the University of Washington. Jaeho Kim acknowledges financial support from the Grover and Creta Ensley Fellowship in Economic Policy at the University of Washington. We thank Dukpa Kim, Charles R. Nelson, Richard Startz, Harald Uhlig, and Eric Zivot for helpful comments.