In this paper we show the consequences of applying a panel unit root test when testing for a purchasing power parity relationship. The distribution of the tests investigated, including the IPS test of Im et al (1997), are influenced by a common stochastic trend which is usually not accounted...

We propose a seasonal cointegration model [SECM] for quarterly data which includes variables with different numbers of unit roots and thus needs to be transformed in different ways in order to yield stationarity. A Monte Carlo simulation is carried out to investigate the consequences of...