Research

Denser housing construction can alleviate rising housing costs, but opponents frequently cite car traffic as a primary concern. We quantify these heterogeneous traffic costs from new residents across the Boston Combined Statistical Area. Using data on households’ intra-metro-area travel, the road network, road speeds, and routing decisions, we estimate monthly traffic counts on every street. We find that moving a house from the 25th percentile of the distribution of nearby street traffic to the 75th percentile decreases its value by 20%, while adding the same number of monthly trips to the street of a similar house at the 75th percentile only decreases its value by 2.7%. We estimate a structural, hedonic model of households’ residential choices and visits to points of interest and find that households are willing to pay to avoid both car traffic on their street and travel time, but that these preferences vary widely across the population. Using the model and estimates of how traffic volumes affect road speeds, we simulate the traffic externalities caused by adding new residents in different locations. We find that a Massachusetts state law targeting a 10% housing stock increase to land near public transit stops causes $3.3 billion in traffic externalities from these new residents, an $820 million reduction relative to spreading those homes uniformly across space. Building those units on thoroughfares instead would decrease welfare costs by an additional $520 million.

We use the abolition of peremptory strikes in Arizona in 2022, which eliminated attorneys' ability to strike prospective jurors without cause, to estimate how jury selection affects differential conviction rates by race. Comparing to New Mexico, we find the differential conviction rates of Hispanic and non-Hispanic defendants in Maricopa County drops by around 13 percentage points immediately after the removal of peremptory strikes. We find no evidence of changes in selection into trial and we find suggestive evidence that the effect is driven by shrinking the ethnicity conviction gap for the judges for whom it was previously the largest.

How do permanent changes in the amount of water available for productive uses affect local communities? Concerns about negative impacts on local economies that sell water have driven repugnance toward water market liberalization and curtailed efforts to promote market re-allocation—a powerful policy tool to adapt to increasing water scarcity. This paper uses the liberalization of water markets in Australia’s Murray-Darling Basin in 2007 to investigate the effects of the re-allocation of water on local economies and residents’ welfare. We exploit differences in endowments of soil productivity to instrument for post-reform changes in water usage to measure their effect on wages, home prices, and populations. Losing water is associated with lower wages, lower rents, and lower populations 14 years on. To quantify the welfare implications, we develop and estimate a residential choice model. The model-implied average willingness to pay to avoid a nearby farmer selling an acre-foot of water is around $50, which is around a quarter of the average market price. We consider different market designs that ensure Pareto improvements for all local communities while achieving the productive efficiency gains of an unfettered market.

Nearly all scientific research is focused on a small fraction of potential topics. This paper argues that such concentration is indicative of allocative inefficiency. We develop a model of sequential investment, wherein scientists select projects by choosing locations in topic space. We show that under various conditions, dense clusters of projects form around a small subset of topics. In particular, we show that if scientist project choice is path dependent, then clustering is nearly always inefficient. Thus, to test for inefficiency, we test for evidence of path dependence. We construct granular data on scientist careers and project choices from the texts of scientific publications in biomedical research. Using idiosyncratic variation in scientists' initial locations in topic space, we provide causal evidence that small changes in initial conditions have permanent impacts on long-term project choice. To quantify the magnitude of this path dependence, we estimate a quantitative version of our model. We show that policies that shift scientists' initial locations—by altering the structure of scientific training and shifting incentives for early-career research—can offset the inefficiencies introduced by path dependence. Our counterfactual exercises highlight, however, that while institutional sources of path dependence can be addressed with better designed policy, some share of this distortion is likely an immutable aspect of the scientific process.

In Federalist systems, the most local tier of government typically has jurisdiction over land use decisions. The decentralization theorem discussed in Oates (1972) and Oates (1999) suggests that these local governments are best suited to cater to their constituents’ preferences. We propose an empirical test of this theory. Chapter 40B, a Massachusetts state law, provides a source of quasi-experimental variation in the level of government with jurisdiction over siting of new housing developments. When less than 10% of a jurisdiction’s permanent housing stock is considered affordable, that jurisdiction loses its discretion over whether new, partially affordable housing developments can be built in its borders. Using the tools developed in Kashner and Ross (2024), we estimate the effect of local control over the siting of new housing developments on the traffic externalities generated by the residents of those developments. We find that new housing developments built when local governments have control over siting decisions cause 35% smaller welfare costs on existing metropolitan area residents due to increased car traffic. This effect is driven by a 55% decrease in welfare costs on households within the siting jurisdiction’s borders, with a statistically insignificant and economically small decrease in traffic externalities on households in other jurisdictions.

Thermal phase curves of short-period planets on circular orbits provide joint constraints on the fraction of incoming energy that is reflected (Bond albedo) and the fraction of absorbed energy radiated by the night hemisphere (heat recirculation efficiency). Many empirical studies of hot Jupiters have implicitly assumed that the dayside is the hottest hemisphere and the nightside is the coldest hemisphere. For a given eclipse depth and phase amplitude, an orbital lag between a planet’s peak brightness and its eclipse—a phase offset—implies that planet’s nightside emits greater flux. To quantify how phase offsets impact the energy budgets of short-period planets, we compile all infrared observations of the nine planets with multi-band eclipse depths and phase curves. Accounting for phase offsets shifts planets to lower Bond albedo and greater day–night heat transport, usually by <1σ. For WASP-12b, the published phase variations have been analyzed in two different ways, and the inferred energy budget depends sensitively on which analysis one adopts. Our fiducial scenario supports a Bond albedo of 0.27, significantly higher than the published optical geometric albedo, and a recirculation efficiency of 0.03, following the trend of larger day–night temperature contrast with greater stellar irradiation. If instead we adopt the alternative analysis, then WASP-12b has a Bond albedo consistent with zero and a much higher recirculation efficiency. To definitively determine the energy budget of WASP-12b, new observational analyses will be necessary.