How does a citizen's decision to participate in political activism depend on the participation of others? We conduct a nation-wide natural field experiment in collaboration with a major European party during a recent national election. In a party survey, we randomly provide canvassers with true...

Many social movements face fierce resistance in the form of a countermovement. When deciding to become politically active, a movement supporter, therefore, has to consider both her own movement's activity, but also that of the opponent. This paper studies the decision of a movement supporter to...

Are political activists driven by instrumental motives such as making a career in politics or mobilizing voters? We implement two natural field experiments in which party activists are randomly informed that canvassing is i) effective at mobilizing voters, or ii) effective for enhancing...

We study participation in right-wing rallies and counterrallies in Germany to examine strategic interactions in political movements. In the leadup to two right-wing rallies, we exogenously shift potential participants’ beliefs about the turnout at the right-wing rally and left-wing...

We develop and estimate a model of jointly optimal income taxes for different types of income. Compared to standard optimal tax formulas, optimal schedular income tax rates additionally depend on cross-elasticities between tax bases capturing fiscal externalities. We discuss two applications:...

How does a citizen's decision to participate in political activism depend on the participation of others? We conduct a nation-wide natural field experiment in collaboration with a major European party during a recent national election. In a seemingly unrelated survey, we randomly provide...

How does a citizen's decision to participate in political activism depend on the participation of others? We examine this core question of collective action in a nation-wide natural field experiment in collaboration with a major European party during a recent national election. In a seemingly...

We study participation in right-wing rallies and counterrallies in Germany to examine strategic interactions in political movements. In the leadup to two right-wing rallies, we exogenously shift potential participants' beliefs about the turnout at the right-wing rally and left-wing counterrally,...

Media outlets are increasingly owned by conglomerates, inducing a conflict of interest: a media outlet can bias its coverage to benefit companies in the same group. We test for bias by examining movie reviews by media outlets owned by News Corp.—such as the Wall Street Journal—and by Time...