This dissertation contains three essays on choice and voting theory. In Chapter

1, a model of stochastic choice is proposed and characterized. Randomness in

choice is driven by variability in the availability of alternatives. Chapter 2 addresses

the classic implementation problem in a spatial setting. A social choice rule is

recommended that can be viewed as a spatial analogue to majority rule as originally

axiomatized by May (1952). Chapter 3 investigates testability, identification, and

estimation in a large class of models used in modeling voting behavior. The models

have relevance to the growing number of online voting platforms.

This dissertation contains three chapters, the first two of which are on decision theory and the last of which is on social and economic networks. In the first chapter, I model a decision maker who is able to evaluate the available options in multiple subjective dimensions or attributes, but is not generally able to aggregate the values of these attributes through a single utility function to rank the available options. This inability arises whenever there are multiple attributes that lead to conflicting ranking over the options. The model that I propose is able to account for a number of violations of standard utility maximization models such as stochastic choice and context dependence, in particular the attraction effect and the compromise effect. I provide an axiomatic characterization of my model. An important feature of this model is that attributes are identified through the observed choices.

The second chapter extends the random utility framework to the realm of choices over menus of alternatives. More specifically, I assume that as modelers we can only observe the aggregate choices of a heterogenous population of decision makers over menus (e.g. restaurants). Furthermore, I assume that each member of the population behaves according to the standard model of choice over menus. Specifically, each decision maker has a well-defined strict preference ordering over individual alternatives (e.g. meals) and chooses an available restaurant that offers the best meal among all the available restaurants. The potential heterogeneity of the population makes the aggregate choices over menus appear stochastic. In the main result of the paper, I provide a characterization of all stochastic choice data over menus that are consistent with a population of standard decision makers.

The third chapter is on social and economic networks and studies the integration of two communities that face a barrier to communicate with one another. We assume that nodes benefit from both direct and indirect connections, but direct connections come also with a cost. We capture the barrier of communication between the two communities by assuming that inter-community links are more costly than intra-community links. In this context, we characterize all integrated structures that are efficient. Next, we determine which of these efficient structures can be also stable. A notable feature of our work is a new class of multi core and periphery structures that we introduce in this paper as parallel hyperstars.

The first chapter studies repeated matching markets, where in every period, a new generation of short-lived workers is matched to a fixed set of long-lived firms on the other. I characterize self-enforcing arrangements for two types of environments. When wages are rigid, as in the matching market for hospitals and medical residents, players can be partitioned into two sets: regardless of patience level, some players can be assigned only according to a static stable matching; when firms are patient, the other players can be assigned in ways that are unstable in one-shot interactions. I also discuss these results’ implications for market design. When wages can be flexibly adjusted, I show that repeated interaction resolves well-known non-existence issues: while static stable matchings may fail to exist with complementarities and/or peer effects, self-enforcing matching processes always exist if firms are sufficiently patient.

The second chapter provides revealed preference characterizations for choices made under various forms of costly information acquisition. We examine nonseparable, multiplicative, and constrained costly information acquisition. In particular, this allows the possibility of unknown time delay for acquiring information. The techniques we use parallel the duality properties in the

standard consumer problem.

The third chapter provides a universal condition for rationalizability by risk-averse expected utility preference in a demand-based framework with multiple commodities. Our test can be viewed as a natural counterpart of a classical test of expected utility, due to Fishburn (1975), in a demand setting.