ALFRED KLEINKNECHT is Professor in the Economics of Innovation at Delft University of Technology. He was previously a senior researcher at the Foundation for Economic Research at the University of Amsterdam and Professor of Industrial Economics and Director of the Economic and Social Institute at the Free University of Amsterdam. PIERRE MOHNEN is Professor of Economics at the Universit? du Qu?bec ? Montr?al and a fellow at the Center for Interuniversity Research and Analysis on Organizations (CIRANO). His main areas of research are the economics of innovation, R&D and productivity. He has published in such journals as the European Economic Review, the Canadian Journal of Economics, the Journal of International Economics, STI Review, Structural Change and Economic Dynamics and Annales d'Economie et de Statistiques.