The aim of this study is to search for a better optimization algorithm in applying unit root tests that inherit nonlinear models in the testing process. The algorithms analyzed include Broyden, Fletcher, Goldfarb and Shanno (BFGS), Gauss-Jordan, Simplex, Genetic, and Extensive Grid-Search. The...

This paper employs smooth transition trend models to investigate the long-run time series behavior of quarterly US labor force participation rates. In particular, we examine whether long-run growth in labor force participation rates can be modeled by smooth transitions between states rather than...