This note studies the geometric ergodicity of nonlinear autoregressive models with conditionally heteroskedastic errors. A nonlinear autoregression of order p (AR(p)) with the conditional variance specified as the conventional linear autoregressive conditional heteroskedasticity model of order q...

This paper considers a sequence of misspecification tests for a flexible nonlinear time series model. The model is a generalization of both the smooth transition autoregressive (STAR) and the autoregressive artificial neural network (AR-ANN) models. The tests are Lagrange multiplier (LM) type...

This paper extends the family of smooth transition autoregressive (STAR) models by proposing a speci.cation in which the autoregressive parameters follow random walks. The random walks in the parameters capture permanent structural change within a regime switching framework, but in contrast to...