| Abstract: | The time series properties of unemployment rates for Germany, Japan, the UK and the US are re-examined. Evidence of nonlinear structure in the residuals of the most parsimonious linear ARMA models is reported for all countries except Japan. Modelling this nonlinearity using SETAR models suggests strong asymmetry in unemployment dynamics and the presence of a possible limit cycle for the UK. However, residual diagnostics for these models indicate remaining structure. Alternative TAR models conditioned on past growth rates of industrial production yield substantial reductions in residual variance over both linear and SETAR counterparts, iid residuals in all cases other than the US, and threshold values at or very near zero, clearly identifying the asymmetric behaviour of unemployment during expansionary and contractionary phases of the business cycle. |
