This paper considers the extension to panel data of models that are specified cross-sectionally in terms of a likelihood. It considers specifically the estimation of stochastic frontier models but the same issue arises in many other models. The model can be estimated for any single value of the...

This paper considers models with time-varying individual effects (also known as factor models). The paper extends Ahn, Lee and Schmidt, Journal of Econometrics, 2001 and Bai, Econometrica, 2003 to allow a parametric function of time for the time factor. It provides a fixed-effects treatment of...

In this paper, we are interested in a stochastic frontier model in which observable characteristics of the firms affect their levels of technical inefficiency. Let u ≥ 0 be the one-sided error reflecting technical inefficiency, and let z be a set of variables that affect u. We write u as...