Incentives and market-based institutions [electronic resource]
Keywords: Economics

In this dissertation, we will study three market-based institutions and the incentives that govern them. The first institution is that of centralized school choice, which has become increasingly important over the past decade. Students submit ordinal rankings over schools and a central mechanism uses those rankings to assign students. We study an important mechanism that is seen in the field, the Boston mechanism, and another mechanism with nice theoretical properties, the Deferred acceptance mechanism (DA), that has been adopted in several large school districts. One of the biggest reasons that DA is theoretically nice is that it makes truthful preference revelation a dominant strategy for the students. In a lab experiment, we show that students fail to truthfully reveal their rankings over schools when it is profitable to do so (under Boston), but tell the truth when it is not (under DA). In this sense, the experiment confirms the intuition that designers of school choice mechanisms should be worried about strategic manipulation of preference reports. We also, however, look at a different preference environment where truth-telling is a Bayes- Nash equilibrium under Boston and a dominant strategy equilibrium under DA. What's more, under this environment, given truthful revelation, Boston yields outcomes that stochastically dominant those of DA from the interim perspective that considers others' preferences unknown. In this environment, we see truth-telling rates that are not significantly different, which means that we might be able to implement better outcomes if we look to mechanisms that implement truth-telling as a Bayes-Nash equilibrium, instead of as a dominant strategy. Next, we look at two-sided labor matches, such as the one used by the National Residency Matching Program (NRMP) to match newly-minted doctors to residency programs. Again, we see two major types of mechanisms -- priority mechanisms that try to implement potential matches in a particular order, and Deferred Acceptance mechanisms, which rely on the Gale-Shapley algorithm. Relative to truthful preference revelation, DA is ex post stable, while priority mechanisms are not. Ex post stability intuitively prevents unraveling. In equilibrium, though, we do not expect truthful preference revelation, and in fact, this leads to instability in the equilibria of both mechanisms. Still, in the field, we see that priority mechanisms tend to unravel, while DA mechanisms do not. This is a puzzle which can be resolved if agents truthfully reveal under DA, in spite of the fact that they could profit by deviating. In the lab, we show that this is exactly what we see, which provides a complementary explanation for the success of DA to the core-convergence-based explanations. Finally, we look at long-distance trade without enforcement. When we think of pre-modern trade, a major problem was the worry that agents carrying goods might abscond with those goods instead of carrying them to their intended destinations. Explanations in the literature have tended to rely on models of reputation. These models, in turn, rely on the theory of infinitely repeated games. This is usually justified via the thought that traders formed some sort of tightly knit community or had some sort of dynastic continuation. We look at the question of finite trade. Although the conventional wisdom is that finite trade would unravel from the last period, we show a mechanism by which this does not happen. Beyond merely making a technical point, we think this model of finite trade provides a good model with which to think about impersonal trade.