Testing for Persistence Change in Fractionally Integrated Models: An Application to World Inflation Rates

In this paper we propose an approach to detect persistence changes in fractionally integrated models based on recursive forward and backward estimation of the Breitung and Hassler (2002) test. This procedure generalises to fractionally integrated processes the approaches of Leybourne, Kim, Smith and Newbold (2003) and Leybourne and Taylor (2003),which are ADF and seasonal unit root type tests, respectively, for the conventional intenger value context. Asymptotic results are derived and the performance of the new procedures evaluated in a Monte Carlo exercise. The ?nite sample size and power performance of the procedures are very encouraging and compare very favourably to available tests, such as those recently proposed by Hassler and Sheithauer (2009) and Sibbertsen and Kruse (2007).We also apply the test statistics introduced to several world inflation rates and and evidence of change in persistence in most series.