Abstract not found

We use simple learning models to track the behavior observed in experiments concerning three extensive form games with similar perfect equilibria. In only two of the games does observed behavior approach the perfect equilibrium as players gain experience. We examine a family of learning models which possess some of the robust properties of learning noted in the psychology literature. The intermediate term predictions of these models track well the observed behavior in all three games, even though the models considered differ in their very long term predictions. We argue that for predicting observed behavior the intermediate term predictions of dynamic learning models may be even more important than their asymptotic properties.

Economists have lately been called upon not only to analyze markets, but to design them. Market design involves a responsibility for detail, a need to deal with all of a market’s complications, not just its principle features. Designers therefore cannot work only with the simple conceptual models used for theoretical insights into the general working of markets. Instead, market design calls for an engineering approach. Drawing primarily on the design of the entry level labor market for American doctors (the National Resident Matching Program), and of the auctions of radio spectrum conducted by the Federal Communications Commission, this paper makes the case that experimental and computational economics are natural complements to game theory in the work of design. The paper also argues that some of the challenges facing both markets involve dealing with related kinds of complementarities, and that this suggests an agenda for future theoretical research.

We create an environment in which congestion forces agents to match inefficiently early. We then introduce one of two centralized clearinghouse mechanisms. One of these has been successfully used to halt this kind of unraveling in a number of labor markets, while the other has failed. When it is costly for �rms and workers to be mismatched compared with the costs of matching early, the experimental observations reproduce the �eld observations. Furthermore, the experiment permits us to observe the transition between a decentralized and a centralized market, both when the centralized market fails to control unraveling and when it succeeds, at a level of detail unavailable in �eld data. Field studies of competitive entry-level professional labor markets reveal a common form of market failure involving the ‘‘unraveling’ ’ of hiring decisions, in which employment contracts from year to year become earlier and earlier in advance of employment, even when this becomes very costly {Roth and Xing 1994}. Sometimes the cause is that the market is organized in

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. Because the market has complementarities between applicants and between positions, the theory of simple matching markets does not apply directly. However, computational experiments show the theory provides good approximations. Furthermore, the set of stable matchings, and the opportunities for strategic manipulation, are surprisingly small. A new kind of “core convergence ” result explains this; that each applicant interviews only a small fraction of available positions is important. We also describe engineering aspects of the design process.

The entry-level market for American gastroenterologists was organized by a centralized clearinghouse from 1986 to 1996. 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. We find that, both before and after the years in which the centralized clearinghouse was used, gastroenterologists are less mobile and more likely to be employed at the same hospital in which they were internal medicine residents than when the clearinghouse was in use. This suggests that the clearinghouse not only coordinates the timing of appointments but also increases the scope of the market, compared to a decentralized market with early appointments.

In the context of entry-level labor markets, we consider the potential transactions that have to be evaluated before equilibrium transactions can be identified. These potential transactions involve offers that are rejected. After an initial phase in which many offers can be proffered in parallel, subsequent potential transactions must be processed serially, since a new offer cannot be made until an outstanding offer is rejected. In this phase even a small time required to process offers and rejections may cause bottlenecks. In many, perhaps most, decentralized labor markets, this means that transactions have to be finalized before there is time for the market to clear, that is, before all the potential transactions that would need to be evaluated in order to reach a stable outcome can in fact be evaluated. This has implications for the strategic behavior of firms and workers. In particular, in deciding to whom to offer a position, a firm may have strong incentives to consider not only its preferences over workers but also the likelihood that its offer will be accepted, since if its offer is rejected it may find that many other potential employees have become unavailable in the interim. The analysis is carried out in connection with the decentralized

The deferred acceptance algorithm proposed by Gale and Shapley (1962) has had a profound influence on market design, both directly, by being adapted into practical matching mechanisms, and, indirectly, by raising new theoretical questions. Deferred acceptance algorithms are at the basis of a number of labor market clearinghouses around the world, and have recently been implemented in school choice systems in Boston and New York City. In addition, the study of markets that have failed in ways that can be fixed with centralized mechanisms has led to a deeper understanding of some of the tasks a marketplace needs to accomplish to perform well. In particular, marketplaces work well when they provide thickness to the market, help it deal with the congestion that thickness can bring, and make it safe for participants to act effectively on their preferences. Centralized clearinghouses organized around the deferred acceptance algorithm can have these properties, and this has sometimes allowed failed markets to be reorganized.

harvard.edu). This work was partially supported by a grant from the National Science Foundation. We also thank David Brenner, M.D., Fred Gorelick, M.D., and Sean Sheehan, M.D., for agreeing to be interviewed about the demise of the gastroenterology match. Robert Beran, Elliott Peranson, and Cody Webb, M.D., helped orient us to the ongoing events in

Abstract not found