Lagged variables are often used as instruments when the generalized method of moments (GMM) is applied to time series data. We show that if these variables follow noncausal autoregressive processes, their lags are not valid instruments and the GMM estimator is inconsistent. Moreover, in this...

In this paper, we propose a Bayesian estimation and prediction procedure for noncausal autoregressive (AR) models. Specifically, we derive the joint posterior density of the past and future errors and the parameters, which gives posterior predictive densities as a byproduct. We show that the...

In this paper, we incorporate time-varying mixing probabilities into univariate and bivariate mixture multiplicative error models. Switching between the regimes is governed by an observable predetermined variable. The models are applicable to positive-valued time series, and are particularly...