Enigma

This paper examines the role of private information in conflict. While acting on information can provide an advantage, using it can expose its source and diminish its value in the long run. I study this trade-off empirically, focusing on the Battle of the Atlantic during World War II. There, Allied merchant ships faced Nazi U-boats, which regularly communicated their positions with German central command using Enigma encryption. The Allies secretly broke these codes. I combine novel data on decrypted messages with records of U-boat and merchant ship losses. Using an event-study design, I show that U-boat sinkings of Allied ships fell by 80 percent in the days following position reports, likely due to the rerouting of merchant ships. In contrast, U-boats’ own survival declined only marginally. Allied strikes were selective, prioritizing high-capacity commanders and increasing over time—consistent with the Allies strategically forgoing benefits to protect their information access. Counterfactual simulations suggest that military intelligence prevented 40 percent of potential shipping losses.

Coffeehouses and the Rise of Science

Coffeehouses emerged as a key social institution in early modern England. In 1962, Jürgen Habermas famously argued that they transformed the public sphere by fostering rational debate, enabling Enlightenment ideas to flourish. This paper tests that claim in the context of Enlightenment science in seventeenth-century London. Exploiting the staggered spread of coffeehouses, we find a substantial increase in the number of applied scientists and scientific instrument shops coinciding with the establishment of the first coffeehouse in a jurisdiction. We argue that coffeehouses fostered this growth by lowering the cost of accessing scientific knowledge and making experimental science more interactive and public. Consistent with this mechanism, coffeehouses especially benefited individuals with weaker ties to elite intellectual circles, strengthened links between theory-oriented scientists and practical instrument makers, and increased the number of experimental instrument shops.

Leveling the Playing Field: Knowledge Production in the Digital Age

80% of all journals are not freely available—even though access to existing knowledge is crucial for pushing the research frontier. In this paper, we examine the impact of Sci-Hub, an online platform providing free access to scientific articles, on knowledge creation. Using data on 300 million geo-coded download requests, and the near-universe of scientific articles we employ an instrumented difference-in-differences design. We find that Sci-Hub has significantly changed consumption patterns of scientific works, with a substitution of references from open- to closed-access publications. In turn, greater access to frontier knowledge resulted in higher-quality research output as measured by citations, but not more publications.

Social Policy and Autocracy: Evidence from East German Administrative Data

This paper studies the role of social policy in shaping citizen-state relations under autocratic rule. I argue that social policies can increase political support especially when they signal recognition—of citizens’ needs, burdens and social identities. To examine this argument, I focus on the introduction of extended maternity leave in former East Germany, a policy that extended material benefits but also signaled attentiveness to women’s dual roles as workers and caregivers. Using administrative data on civilian bureaucrats, I show that women giving birth after the policy reform saw a surge in membership of the ruling party compared to women giving birth shortly before. I also find suggestive evidence of gendered spillovers: first, affected grandmothers were more likely to become members, but not grandfathers. Second, in present-day surveys, likely affected daughters lean more towards left-wing ideology.