In this paper we analyze GMM with semi-weak instruments. This case includes the standard GMM and the nearly-weak GMM. In the nearly-weak GMM the correlation between the instruments and the first order conditions decline at a slower rate than root T. We find an important difference between the...

This paper is concerned with estimating the additive components of a nonparametric additive quantile regression model. We develop an estimator that is asymptotically normally distributed with a rate of convergence in probability of $n^{-r/(2r+1)}$ when the additive components are $r$-times...

A method of principal components is employed to investigate nonlinear dynamic factor structure using a large panel data. The evidence suggests the possibility of nonlinearity in the U.S. while it excludes the class of nonlinearity that can generate endogenous fluctuation or chaos

In this paper, local relationship between per capita health expenditure and GDP is investigated with local quantile regressions. The advantage of using local quantile regressions is the assumption of homogeneity on per capita health care expenditure could be relaxed so that number of countries...