Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
A recent article (Koop and Tobias, 2004) proposes a direct way to characterize the extent of heterogeneity in returns to education. They investigate the adequacy of several competing models and conclude that returns to schooling are heterogeneous and are best modelled as a bivariate normal distribution. The results of this replication paper basically agree with the authors. Copyright © 2005 John Wiley & Sons, Ltd.