Abstract

The Role of Wait Time Disclosures in Public Housing: Evidence from Seattle: This paper studies how providing wait time information affects applicant choices and allocation outcomes in a public housing allocation mechanism, where applicants choose their preferred communities and receive housing units on a first-come, first-served basis. Under such a mechanism, applicants' choices depend on their preferences and subjective beliefs about expected wait times for each community. Using administrative data from the Seattle Housing Authority, I study the effect of its disclosure of Historical Wait Time (HWT) information, which is provided as a discrete HWT signal for each community, such as "2-3 years" or "Not Available". I build and estimate a structural model assuming applicants form their subjective wait time beliefs based on these disclosed signals. Variation in HWT signals, both across communities and for the same community over time, allows for identification of preferences and beliefs using only choice data. The estimation reveals that applicants' beliefs respond non-linearly to the disclosed wait times. The subjective disutility of waiting is the highest for moderately long HWT signals, as the penalty rises initially before falling for extremely long HWT signals. Holding housing availability constant, counterfactual simulations show that withholding wait time information improves overall match quality by reallocating units to higher-need applicants by deterring lower-need applicants from applying, and forcing those who apply to base their choices on underlying preferences instead of the wait time signals. In particular, the counterfactual policy increases the average utility for housed applicants by 1.76% and reduces their realized wait time by 1.06%, boosting the overall efficiency of the public housing system. Strategic Interactions in Ambulance Diversion: Evidence from San Francisco County: Ambulance diversion is the practice by which Emergency Departments (EDs) signal that they are unable to accept more ambulance patients, thereby discouraging incoming transports. While intended by EMS agencies solely as a response to internal congestion, this paper investigates whether diversion decisions are also driven by strategic interactions, specifically whether a hospital's likelihood of diverting is directly influenced by the diversion status of its peers. Using administrative data from San Francisco County, California, between 2015 and 2020, we first document a cascade of diversions where the likelihood of a hospital declaring diversion increases monotonically with the number of peers already on diversion. To determine whether this pattern is driven by strategic interactions rather than correlated demand shocks, we estimate a Cox Proportional Hazards model of the time to diversion, defined as the duration a hospital remains open before declaring diversion, while controlling for time-varying internal congestion measures including ambulance inflow, ED walk-in volume, and inpatient census. Our estimates confirm that peer diversion significantly influences the timing of diversion, as the hazard of declaring diversion increases monotonically with the number of diverting peers, peaking at a 125.0% increase when three peers are on diversion compared to none. We also observe substantial heterogeneity in diversion behavior across hospital types: while community hospitals exhibit high sensitivity to peer behavior, an insurer-owned hospital that internalizes medical costs remains mostly insulated from these strategic interactions. These findings provide empirical evidence that diversion is not solely a response to internal congestion but a structural feature of strategic interactions within the hospital network. Search Frictions, Firm Efficiency, and Market Concentration: Theory and Evidence: Conventionally, rising market concentration is viewed as a signal of weakening competition. In this paper, we investigate a mechanism where concentration arises from the opposite force: the intensified competition as a result of the reduction of search frictions. This paper investigates the impact of declining search frictions on market concentration and equilibrium prices. We develop and calibrate a sequential consumer search model featuring firms with asymmetric marginal costs. The theoretical calibration reveals that lower search costs enable cost-efficient firms to capture market share, thereby increasing market concentration. However, the predicted effect on average market prices is non-monotonic: moderate search frictions induce aggressive pricing from efficient firms to incentivize searches, whereas negligible frictions allow efficient firms to dominate without offering deep discounts. We test these predictions using data from the US domestic airline industry between 1990 and 2001, a period characterized by the adoption of electronic ticketing and online booking. Consistent with the model, we find that the industry's efficiency leader, Southwest Airlines, significantly expanded its market share. Using an instrumental variable approach to control for the endogeneity of market structure, we resolve the theoretical ambiguity regarding price effects. We find that while higher market concentration generally exerts upward pressure on airfares, the expansion of the efficiency leader exerts a dominant downward pressure. These findings imply that concentration arising as a natural outcome of competition can coincide with lower market prices, distinguishing it from concentration driven by anti-competitive behavior.

Committee Chair

George-Levi Gayle

Degree

Doctor of Philosophy (PhD)

Author's Department

Economics

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

3-31-2026

Language

English (en)

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Economics Commons

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