UNEMPLOYMENT AND HYSTERESIS: A NONLINEAR UNOBSERVED COMPONENTS APPROACH

The aim of this paper is to find a possible hysteresis effect on unemployment rate series from Italy, France and the United States. We propose a definition of hysteresis taken from Physics which allows for nonlinearities. To test for the presence of hysteresis we use a nonlinear unobserved components model for unemployment series. The estimation methodology used can be assimilated into a threshold autoregressive representation in the framework of a Kalman filter. To derive an appropriate p-value for a test for hysteresis we propose two alternative bootstrap procedures: the first is valid under homoskedastic errors and the second allows for general heteroskedasticity. We investigate the performance of both bootstrap procedures using Monte Carlo simulation.