This paper considers estimation of panel data models with fixed effects. First, we will show that a consistent "unrestricted fixed effects" estimator does not exist for autoregressive panel data models with initial conditions. We will derive necessary and sufficient conditions for the...

This paper proposes new ℓ1-penalized quantile regression estimators for panel data, which explicitly allows for individual heterogeneity associated with covariates. We conduct Monte Carlo simulations to assess the small sample performance of the new estimators and provide comparisons of new...

A panel data set covering 145 countries between 1960 and 2010 has been investigated closely by using models of parameter heterogeneity. The Functional Coefficient Model (FCM) introduced by Cai, Fan and Yao (2000) allows estimated parameters of growth determinants to vary as functions of one or...