Using 15 years worth of additional data, a study is carried out to explore the extent to which the results in Rothman (1991) still hold. Using raw unfiltered data, the aggregate unemployment rate appears to be a Neftci-type symmetric process. But use of two detrending procedures produces strong...

Asymmetric behavior has been documented in post-war quarterly U.S. unemployment rates. This suggests that improvement over conventional linear forecasts may be possible through use of nonlinear time series models. In this paper an out-of-sample forecasting competition is carried out for a set of...