Departmental Research Seminar

Competition and Consumer Welfare in Airport Slot Allocation
I study how the current airport slot allocation mechanism affects airline competition and consumer welfare. Currently, airlines are required to use their slots at least 80% to keep them for next year. My central finding is that this requirement leads airlines to add flights that exacerbate congestion, yet it also intensifies competition on major routes. To show this, I build and estimate a structural model of airline demand and route choice using EU data. My estimates show that while some airports cease to be congested if current usage doesn't affect future slot allocations, such a change reduces consumer welfare due to the reduced competition. Furthermore, even if a social planner reallocates slots to maximize consumer surplus, the rule change still causes a substantial welfare loss. This highlights that reforms prioritizing allocative efficiency over this competitive mechanism risk substantial harm to consumers.

Social Returns to Conservation: Environmental Quality Incentives Program, Cover Crops, and Water Quality in the Midwest

Agricultural runoff significantly contributes to nutrient water pollution, leading to harmful environmental consequences and posing public health risks. Cover cropping (CC), the practice of planting non-cash crops during off-seasons, has gained attention as a conservation strategy to mitigate these impacts. USDA's Environmental Quality Incentives Program (EQIP), the largest working land conservation program in the U.S., has increasingly supported CC adoption through cost-share subsidies. This study assesses the social returns of EQIP in enhancing surface water quality through CC adoption in the Midwest. This paper conducts an event study to quantify the program's effect on CC adoption, using a novel 17-year satellite-derived dataset of field-level CC adoption and exploiting the staggered rollout of EQIP's Mississippi River Basin Healthy Watershed Initiative (MRBI). The estimates reveal that EQIP MRBI increased CC adoption by 1.46 percentage points over an average four-year treatment exposure, with persistent effects beyond program funding. The study then performs panel data analyses, linking CC adoption to harmonized water-quality data and leveraging the variation between upstream and downstream locations. Empirical results show that a one-percentage-point increase in upstream CC adoption share reduces total nitrogen in surface water by 0.88%. Combining both estimates, a back-of-the-envelope calculation yields a benefit-cost ratio of 2.22, which indicates that EQIP CC subsidies deliver substantial water-quality benefits. At the same time, while EQIP subsidies generate persistent adoption of CC, their additionality is limited, underscoring the need for sharper targeting to enhance environmental effectiveness.

Talent, Trust, and Health: The Effects of the First Female Physicians

How did the entry of women into historically male high-skill occupations shape the productivity and organization of those professions? This paper examines the large-scale entry of female doctors into the medical profession following the decision to open the world’s first full-length medical school for women in the Russian Empire in 1872. I digitize novel annual data on physician employment and vital statistics in over 300 districts from 1876–1910, as well as data on direct healthcare provision metrics from 1876-1888. Leveraging these data, I study the effects of the hiring of the first female physicians on health outcomes. Using a staggered difference-in-differences design based on quasi-random timing of replacement hires of general practitioners, I find that female physician entry led to large and persistent declines in infant mortality (6\%) and in young adult mortality of both sexes (7-13\%), resulting in faster population growth (10\%). The first female physicians improved hospital care and drew more female patients into formal medical care, evidenced by their displacement of midwives.  I further find that female physicians fleeing the 1917 Russian Revolution into the US reduced infant mortality in rural US counties. I develop a conceptual framework to disentangle positive selection of women into medicine from demand-side concordance preference mechanisms, and show that observed effects came from both the female physicians' greater overall effectiveness compared to the male doctors and from increased care-seeking among women.

Networks and Social Capital

We formalise the idea that networks allow individuals to build their social capital by receiving an access to resources embedded in their connections. Higher social capital, in turn, results in increased productivity. We emphasize the trade-off between connecting with many individuals to get direct access to their resources, and connecting with a few (but well connected) individuals who could provide indirect access to resources of their connections. The latter option implies degrading the quality of resource access compared to the former, but can result in cost reduction by minimizing the number of links the focal individual needs to maintain. Based on a formal model, we quantify the value of social capital for an individual embedded in an arbitrary network. We show that the relationship between the direct resource access share (i.e., the resources that the individual can access through direct connections as a fraction of all available resources in their network) and the value of the focal individual's social capital has a U shape. In collaboration context, we also derive implications of the model regarding the effects of the collaboration patterns among other scientists on the productivity of the focal scientist. The analysis of patenting data of French inventors supports hypotheses derived from the formal model. Implications for the optimal co-author selection, as well as the optimal research team design are discussed.