Paris Empirical Political Economics Seminar (PEPES)

We argue that societies with higher fertility experience increased levels of emigration. During the Age of Mass Migration, persistently high fertility created a large reservoir of surplus labor that could find better opportunities in the New World. We denote such migrations, from labor-abundant to land-abundant regions, as Malthusian migrations. Our results hold in a variety of datasets and specifications, across countries, regions, individuals, and periods. Using linguistic distance from French and twin births as instruments for fertility in crowdsourced genealogical data, we estimate a large effect of fertility on out-migration. Within households, later born children were more likely to migrate as fertility increased, particularly in regions with egalitarian inheritance. We develop a Malthusian model allowing for emigration as a way to escape population pressures, alleviating the negative effects of high fertility and contributing to the emergence of modern economic growth.

The study measures scientists’ polarization on social media and its impact on public perceptions of their credibility. Analyzing 98,000 scientists on Twitter from 2016 to 2022 reveals significant divergence in expressed political opinions. An experiment assesses the impact of online political expression on a representative sample of 1,700 U.S. respondents, who rated vignettes with synthetic academic profiles varying scientists’ political affiliations based on real tweets. Politically neutral scientists are viewed as the most credible. Strikingly, on both the ’left’ and ’right’ sides of politically neutral, there is a monotonic penalty for scientists displaying political affiliations: the stronger their posts, the less credible their profile and research are perceived, and the lower the public’s willingness to read their content. The penalty varies with respondents’ political leanings.

The rapid growth of nuclear power plants (NPP) declined dramatically after Chernobyl, especially in countries with democratic governments which had the highest number of NPPs at the time. To understand the mechanisms driving such change, we examine two case studies in detail: the United States and the United Kingdom. In the U.S., we document that: (a) after the Chernobyl accident, campaign contributions to House and Senate races from fossil fuel special interest groups became strongly associated with negative votes on nuclear-related bills, and such donations increased significantly; and (b) newspapers with more fossil fuel advertisements published more anti-nuclear articles after Chernobyl, while we do not observe significant changes in advertisement spending by the fossil fuel industry. In the U.K., MPs sponsored by mining unions were much more likely to give anti-nuclear speeches in parliament after Chernobyl. We examine air pollution as a downstream outcome of reduced nuclear investment. We estimate that the decline in NPP caused by Chernobyl led to the loss of approximately 141 million expected life years in the U.S., 33 in the U.K. and 318 million globally.

We propose a theory of protest dynamics with heterogeneous protest technology and intensity. The ability to mobilize online reduces the likelihood of coordination failures at both the extensive (engagement) and intensive (violence) margins. Social media can initially help launch massive protests, but then encourage radical factions to turn violent and drive out moderates. Using both online and offline data, we show that the 2018 Yellow Vest uprising in France followed such a crowd-in-then-crowd-out sequence: early online and offline mobilizations reinforced each other, but online discussions quickly radicalized, moderates left, and a handful of violent protesters took over the streets.

We study the evolution of female representation in editorial roles for 15 top journals in economics from 1960 to 2019. We first document that the share of women in editorial roles has steadily increased over the past six decades. Second, we investigate whether this increase is due to an expansion of the pool of qualified female economists, or due to a change in the preference for appointing women. We find evidence for both using a large database on detailed CVs of more than 37,000 economists. Third, we study the implications of female editors on the type and quality of accepted papers and potential trickle down effects on female authors’ publishing prospects. Finally, to understand whether there are gender gaps in the probability of being offered and/or of accepting editorial positions, we administer a large-scale survey among most prominent scholars in economics. We only find evidence for the offering channel.

How does culture change in response to major institutional shifts? What is the role of culture in selecting and stabilizing new institutional equilibria in critical junctures? We study the collapse of the Holy Roman Empire (1789–1815), when half of the Central European population changed rulers. Our annual data on 44 million geolocated birth records between 1700 and 1850 provide a real-time measure of identity choices. In cities that changed rulers, the name distribution changed, becoming more dispersed, unique, and polarized. Using detailed records on diplomatic negotiations, we construct comparable control groups to isolate these effects, which emerged immediately and persisted over time. Examining mechanisms, we provide evidence suggesting that the transition increased uncertainty and eroded the supply of loyalist identity, creating an identity vacuum that competing stakeholders — religious and nationalist groups — actively filled. These cultural shifts became institutionalized, fostering tensions with the new regimes. Our findings underscore the dual challenge of cultural and administrative integration in state-building after regime transitions.