Because no marketplace operates in isolation from the larger world, marketplace designs may need to adapt to changes in the larger environments. I discuss such changes in connection with the labor markets for new doctors, new Ph.D. economists, and for kidney exchange transplants. But while...

We report on the design of the new clearinghouse adopted by the National Resident Matching Program, which annually fills approximately 20,000 jobs for new physicians in the United States. Because that market exhibits many complementarities between applicants and between positions, the theory of...

From 1986 through 1997 the entry-level market for American gastroenterologists was organized by a centralized clearinghouse. Before, and since, it has been conducted via a decentralized market in which appointment dates have unraveled to well over a year before the start of employment. The...