On the Accuracy of Bootstrap Confidence Intervals for Efficiency Levels in Stochastic Frontier Models with Panel Data Myungsup Kim University of North Texas Yangseon Kim East-West Center Peter Schmidt ∗ Michigan State University February 2007 Abstract We study the construction of confidence intervals for efficiency levels of individual firms in stochastic frontier models with panel data. The focus is on bootstrapping and related methods. We start with a survey of various versions of the bootstrap. We also propose a simple parametric alternative in which one acts as if the identity of the best firm is known. Monte Carlo simulations indicate that the parametric method works better than the per- centile bootstrap, but not as well as bootstrap methods that make bias corrections. All of these methods are valid only for large time-series sample size (T ), and correspondingly none of the methods yields very accurate confidence intervals except when T is large enough that the identity of the best firm is clear. We also present empirical results for two well-known data sets. JEL Classifications: C15, C23, D24 Keywords : Stochastic frontier, bootstrap, efficiency * The third author gratefully acknowledges support under a Marie Curie Transfer of Knowledge Fellowship of the European Community’s Sixth Framework Program at the University of Crete during Fall 2006 under contract MTKD-CT-014288. 1