Received stochastic frontier analyses with panel data have relied on traditional fixed and random effects models. We propose extensions that circumvent two shortcomings of these approaches. The conventional panel data estimators assume that technical or cost inefficiency is time invariant....

Fixed-effects models have become increasingly popular in social-science research. The possibility to control for unobserved heterogeneity makes these models a prime tool for causal analysis. Fixed-effects models have been derived and implemented for many statistical software packages for...