This paper considers index models, such as neural network models and smooth transition regressions, with integrated regressors. These are the models that can be ued to analyze various nonlinear relationships among nonstationary economic time series. Asymptotics for the nonlinear least squares...

This paper utilizes asymptotic expansions to investigate alternative forms of the Ward set of nonlinear restrictions. Some formulae for the asymptotic expansion of the distribution of the Wald statistic are provided for a general case. When specialized to the simple cases that have been studied...

Instrumental variable (IV) estimation methods that allow for certain nonlinear functions of the data as instruments are studied. The context of the discussion is the simple unit root model where certain advantages to the use of nonlinear instruments are revealed. In particular, certain classes...

In this paper we introduce a new view on the distributions of unit root tests. Taking a contour given by the fixed sum of squares instead of the fixed sample size, we show that the null distributions of most commonly used unit root tests such as the ones by Dickey-Fuller (1979, 1981) and...

This paper introduces an iterative method to estimate the cointegrating vectors in the error correction models. The method provides the asymptotically efficient estimators for the cointegrating vectors if iterated once or more. If it is iterated until convergence, we may obtain the maximum...

This paper considers asset pricing models with stochastic differential utility incorporating decision makers' concern with ambiguity on true probability measure. Under a representative agent setting, we empirically evaluate alternative preference specifications including a multiple-priors...