Is there really hysteresis in the OECD unemployment rates? New evidence using a Fourier panel unit root test

We investigate the hysteresis hypothesis by proposing a heterogeneous panel unit root test that allows for gradually changing trends and cross-sectional dependence (CSD) among panel members using a flexible Fourier form. Inconclusive results from previous studies are potentially due to using very restrictive specifications with homogenous break structures and/or exogenously determined abrupt breaks. We seek to address these limitations by employing general specifications that are more capable of characterising the true data generation process of unemployment and by allowing for spill-over effects using a bootstrapping procedure to accommodate CSD that must be considered in a globalized world. Extensive simulations suggest that the failure to take structural breaks and CSD into account can lead to misleading conclusions about whether the unemployment rate is stationarity. We apply our test procedure to unemployment data for 23 OECD countries and find conclusive evidence against the hysteresis hypothesis for all these countries.