We study the asymptotic covariance function of the sample mean and quantile and derive a new and surprising characterization of the normal distribution: the asymptotic covariance between the sample mean and quantile is constant across all quantiles, if and only if the underlying distribution is...

This article uses a nonparametric varying coefficient panel data model to study the convergence of real GDP per capita among 120 world economies for the sample period of 1980-2010. The estimates show that the indirect contribution of initial income via the control variables is important. The...

This paper studies the income inequality and economic development relationship by using unbalanced panel data of OECD and non-OECD countries for the period 1962 - 2003. The nonparametric estimation results show that income inequality in OECD countries are almost on the backside of the inverted-U...