Professor of economics at the University of Mannheim, Germany, since 2004. He obtained a Diploma degree (1990) and a Ph.D. (1994) in Economics from the University of Bonn. From 1994-1999 he worked as an Assistant Professor of Economics at Indiana University in Bloomington, USA, and from 1999-2004 as an Assistant / Associate Professor (with tenure) of Economics and International Affairs at the University of Colorado in Boulder, USA.
Member of the Scientific Advisory Board to the Federal Ministry for Economic Affairs and Energy in Germany. From 2013 to 2018 he was the Chairman of the Independent Advisory Board to the German Stability Council, the independent fiscal institution in Germany. His fields of interest in research and teaching are public finance and international trade. His research has appeared in outlets such as the American Economic Review, European Economic Review, Journal of Public Economics, and Economic Journal.