This paper investigates the hypothesis of a unit root in inflation for 13 OECD countries over the period 1957-2005, taking into account cross-sectional dependence and multiple mean shifts. We conduct unit root testing with the more powerful unit root tests with cross-dependence proposed by Smith et al. [Smith, L. V., Leybourne, S., Kim, T., & Newbold, P. (2004). More powerful panel data unit root tests with an application to the mean reversion in real exchange rates. Journal of Applied Econometrics, 19(2), 147-170] and a bootstrap version of the panel stationarity test of Hadri [Hadri, K. (2000). Testing for stationarity in heterogeneous panel data. The Econometrics Journal, 3(2), 148-161.], which provide inconclusive evidence on the time series properties of OECD inflation rates. To shed some light on this issue, we employ the recently developed panel stationarity test of Carrión-i-Silvestre et al. [Carrión-i-Silvestre, J. L., Del Barrio, T., & López-Bazo, E. (2005). Breaking the panels: An application to the GDP per capita. The Econometrics Journal, 8(2), 159-175] that assumes a highly flexible trend function by incorporating an unknown number of breaks in level. Overall, our confirmatory analysis renders clear-cut evidence in favor of regime-wise stationarity. Furthermore, the breaks in inflation detected are closely associated with macroeconomic shocks and changes in monetary policy.
