Who Fed China? with Asger M. Wingender (1. version: October 2023, latest version May 2025)
China liberalized imports of agricultural goods upon WTO accession, triggering an unprecedented demand shock to global agriculture. However, the Chinese self-sufficiency policy still limits imports of certain agricultural products. We exploit this variation across products to trace the effects of Chinese demand from the global level to the country level, and down to the local level in Brazil and the United States, China's main suppliers. Across all levels of aggregation, we find that cropland expanded to meet Chinese demand to an extent that initial fears of soaring food prices proved to be unfounded. While benefiting farmers and farm workers, we find that the cropland expansion put significant pressure on global forests. Our study provides the first causal estimates of the effects of a demand shock to global agriculture..Lec Echos (in French) [English version here]
communities.
School Closures, Mortality, and Human Capital: Evidence from the Universe of Closures during the 1918 Pandemic in Sweden with Christian M. Dahl, Peter S. Jensen, Martin Karlsson, and Daniel Kühnle., RR AEJ:Policy
This study investigates the impact of primary-school closures during the 1918 Pandemic in Sweden on mortality and the long-run outcomes of children. Combining the universe of death certificates for over 500,000 individuals from 1914 to 1920 with newly-collected archival data on school closures in more than 2,100 school districts, we employ high-frequency event studies at both weekly and daily intervals to examine the relationship between mortality and school closures. Our findings show that schools were closed in response to a local surge in influenza-related deaths two weeks prior to the closure. Next, we exploit the speed of closure and document that implementing school closures faster significantly reduced peak-level mortality rates, effectively saving the lives of primary-aged individuals. Finally, we track the long-term outcomes of the affected school children (around 100,000 per school grade) throughout their life cycle and compare them to those who were too young to attend school during the pandemic school closures. The precise estimates reveal relatively minor and mostly inconsequential effects of the closures on various outcomes, including longevity, employment, and income.Left in Charge: Political Rule and the Rise of Local Welfare with P.S. Jensen
We study how institutional constraints on executive selection shape redistributive policy, using a 1919 Danish reform that allowed town councils to democratically elect mayors. While the reform applied uniformly across towns, it made left-wing executive control politically feasible for the first time, particularly in towns with stronger prior support for the Social Democratic party. Exploiting predetermined Social Democratic vote shares from the 1917 election interacted with the post-reform period, we identify the causal effect of Social Democratic executive control on local public finance. We show that Social Democratic mayors substantially increased social spending, especially on poor relief and public assistance, with these expansions financed primarily through higher direct taxes. We find no robust evidence that these policies reduced local economic activity. The results highlight how removing institutional constraints on executive selection can translate latent voter preferences into concrete redistributive policy outcomes.
Redistribution, Local Spending, and Growth: Evidence from the Origins of a Municipal Equalization Fund with Peter Sandholt Jensen
This paper examines how intergovernmental transfers affect local government behavior and economic outcomes during the early stages of welfare state formation in Denmark. We exploit a 1937 reform that reimbursed municipal spending on social, medical, and school services (``MEF grants''). Using newly digitized annual panel data and a shift-share like IV strategy, we show that these grants expanded municipal budgets (crowding-in), reduced income inequality, and did not reduce average income or firm profitability. These findings contribute to long-standing debates on the equity-efficiency tradeoff and show that redistributive transfers can expand local welfare capacity without incurring significant growth costs.The Rise of Unions: Evidence from a National Expansion of Unemployment Insurance Access with Marius F. Gunnesmo and Peter S. Jensen
We examine the long-run effects of a temporary expansion of access to unemployment insurance (UI) in Denmark in 1917. The reform suspended a 12-month waiting period for benefit eligibility, allowing new members to access help from state-subsidized UI funds immediately. Using occupation-specific panel data from 1910 to 1940 and an event-study design, we find that occupations with larger increases in UI take-up during the reform experienced persistent growth in both UI-fund and union membership, along with geographic expansion of union presence. These effects remained long after the policy was repealed. In contrast, we find no evidence of increased unemployment, prolonged unemployment durations, wage growth, or labor market conflicts suggesting that the reform increased institutional coverage without distorting labor market outcomes. Our findings show how short-lived social policy reforms can trigger lasting organizational change by lowering entry barriers to collective insurance systems and expanding the base of labor organization.Religion as Social Insurance: Evidence from the Great Mississippi Flood of 1927 with Philipp Ager, Ezra Karger, and Lars Lønstrup. Latest version: 2024