Testing for Conditional Convergence in Variance and Skewness: The Firm Size Distribution Revisited

This article derives generalized method of moment-based Wald tests for conditional convergence in terms of the second and third central moments (conditional "σ"- and "ζ"-convergence). Monte Carlo simulations indicate that the proposed tests are properly sized and equipped with enough power for sample sizes in excess of 1,000 observations. We apply the Wald tests to a comprehensive sample of Austrian firms. The estimation results indicate a substantial reduction in both the second and third central moments of log firm size over time for the younger age cohorts. For older ones, the log-normal distribution is a valid description of their size distribution. Copyright (c) Blackwell Publishing Ltd and the Department of Economics, University of Oxford, 2010.