Benjamin K. Couillard

Research

Job Market Paper (2025-26)

• Couillard, Benjamin K. (2026). "Build, Baby, Build: How Housing Shapes Fertility" 

  • draft available here

  • Abstract: Many developed countries face low and falling birthrates, potentially affected by rising costs of housing. Existing evidence on the fertility-housing cost relationship typically uses geographic variation (raising selection issues), neglects unit size, and says little about policy. To progress on these fronts, I first specify a dynamic model of the joint housing-fertility choice allowing choices over location and house size, estimated using US Census Bureau data. I extend `micro-moment' techniques (Petrin, 2002; BLP, 2004) both to circumvent data constraints and to incorporate heterogeneous residuals, which can prevent misspecification. Housing choice estimates confirm a Becker quantity-quality model’s predictions: large families are more cost-sensitive, and so rising housing costs disincentivize fertility. To study the causal effect of rising housing costs on fertility, I vary them directly within the model, finding that rising costs since 1990 are responsible for 11% fewer children, 51% of the total fertility rate decline between the 2000s and 2010s, and 7 percentage points fewer young families in the 2010s. Policy counterfactuals indicate that a supply shift for large units generates 2.3 times more births than an equal-cost shift for small units. This analysis concludes that the supply of housing suitable for families can meaningfully contribute to demographic sustainability. 

  • Media coverage: New York Times, Marginal Revolution, Vox, New York Post, Newsweek, Toronto Star, American Enterprise Institute, Irish Independent, Conflit, El Liberal, City Journal, Yahoo, Institute for Family Studies, Investopedia, Iona Institute, Boyd Institute, Pacific Research Institute, Realtor.com, VV Guide, The Mortgage Point, Forum Nadlan USA, California YIMBY, Don't Worry About The Vase

Publications 

• Brodeur, Abel; Derek Mikola; Nikolai Cook; Replication Games collaborators, incl. Benjamin K. Couillard (2025). “Mass Reproducibility and Replicability: A New Hope.” Nature. IZA Discussion Paper No. 16912.

  • full text available here

• Couillard, Benjamin K.; Christopher L. Foote; Kavish Gandhi; Ellen Meara; Jonathan Skinner (2021). “Rising Geographic Disparities in US Mortality.” Journal of Economic Perspectives, 35(4): 123–146. 

  • full text available here

Working Papers

• Couillard, Benjamin K. (2026). "Decomposing Racial Disparities in Pollution Exposure." 

  • draft available here

  • Abstract: Racial minorities in the United States bear disproportionate exposure to environmental hazards, but the extent to which this reflects race itself versus correlated economic and demographic characteristics remains unknown. I decompose racial disparities in pollution exposure using a Bayer et al. (2007) neighbourhood sorting model estimated on a four-decade national panel of harmonized census tracts, with preferences varying over race, income, tenure, age, and presence of children. To estimate this heterogeneity from public data, I exploit the sufficiency of observed marginal distributions for the first-stage log-likelihood. Counterfactuals that reweight each minority group’s non-racial demographics to match the white distribution reveal that these characteristics explain little of the disparity: no demographic variable meaningfully accounts for racial gaps in PM10 exposure, and tenure—a proxy for wealth—accounts for only 15–30% of disparities in proximity to Toxic Release Inventory facilities, with other variables adding negligible additional explanatory power. These results weigh against the view that racial pollution disparities primarily reflect rational sorting given fewer economic resources, and point instead toward race-specific mechanisms including discriminatory siting, constrained choice sets, or heterogeneous preferences for unobserved amenities correlated with pollution.

• Couillard, Benjamin K. (2026). "Identification From Marginal Distributions In Logit Models With Observed Heterogeneity."

  • draft available here

  • Abstract: In this paper I study identification of logit discrete choice models from marginal distributions alone. In fields like urban economics that use these models, unobservability of the joint distribution of agent choices and characteristics is treated as a binding data constraint, whereas in empirical industrial organization marginal distributions are used to circumvent that constraint and as the form in which microdata enters estimation. I borrow from the contingency table literature to provide necessary and sufficient conditions for point-identification of logit models with observed heterogeneity from marginal distributions. These results also show that in models without random coefficients, the standard assumption in empirical IO of residual homogeneity almost surely results in an empty identified set. I verify these predictions using Monte Carlo simulations. 

  • draft available here

• Couillard, Benjamin K. & Christopher L. Foote (2019). “Recent Employment Growth in Cities, Suburbs, and Rural Communities.” Federal Reserve Bank of Boston Working Paper No. 19–20.

  • full text available here

Works in Progress

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