Correspondence: Robert, Robert, Tuck School of Business, 100 Tuck Hall, Hanover, HH, USA. Tel: +1 603 646 8137; Fax: +1 603 646 1308; E-mail: robert.shumsky@dartmouth.edu

¹Robert Shumsky is Associate Professor of Business Administration at the Tuck School of Business. He has research and teaching interests in operations management and decision science. His current research focuses on the interactions among quality, flexibility and efficiency in service systems. He has conducted research on the US air traffic management system and studied transportation operations for state agencies and the Federal Aviation Administration. He has also served as a consultant for both manufacturing and service operations, including call centres and health-care providers. Prior to joining Tuck, he was a faculty member at the Simon School of Business at the University of Rochester. He holds a PhD and MS in Operations Research from the Massachusetts Institute of Technology, and a BA in Applied Mathematics from Harvard University.

Received 21 February 2005.