We study the effects of a voluntary skill certification scheme in an online freelancing labour market. We show that obtaining skill certificates increases freelancers' earnings. This effect is not driven by increased freelancer productivity but by decreased employer uncertainty. The increase in...

At the turn of the millennium three frequently cited potential causes of new challenges for wage p olicy in Germany are revisited in this study: skilled-biased technological progress, the increasing international integration of labor and product markets, and the monetary integration of the EMU....