1. Department of Information and Decision Sciences, Carlson School of Management Minneapolis, Minnesota 55408;
2. Operations and Information Management, University of Connecticut, Storrs, Connecticut 06269;
3. Faculty of Management, Economics, and Social Sciences, University of Cologne, 50923 Cologne, Germany;
4. Rotterdam School of Management, Erasmus University, 3062 PA, Rotterdam, The Netherlands;
5. Decision Sciences & Systems, Department of Computer Science, Technical University of Munich, Boltzmannstraße 3, 85748 Garching/Munich, Germany