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Firms often use social networks to find workers, limiting the pool of potential applicants. We conduct a field experiment subsidizing firms’ formal vacancy posting. The subsidies increase non-network employee search and shift vacancies towards high-skilled positions. Post-treatment, firms continue searching for high-skilled workers despite reverting to network-based search. This change in skill requirements does not increase vacancy posting or hiring, suggesting substitutability between workers of different skill levels. Finally, we experimentally show that information asymmetries about applicants’ skills do not limit firms’ formal search. Our results highlight that exposure to different labor market segments can permanently change firms’ labor demand.

@article{hensel2026formalized,
  author  = {Hensel, Lukas and Tekleselassie, Tsegay and Witte, Marc},
  title   = {{Formalized Employee Search and Labor Demand}},
  journal = {Journal of Development Economics},
  year    = {2026},
  note    = {Forthcoming}
}

We conduct a natural field experiment with a major European party to test whether giving party supporters more voice increases their engagement in the party’s electoral campaign. In the experiment, the party asked a random subset of supporters for their opinions on the importance of different policy areas. Giving supporters opportunities to voice their opinions increases their engagement in the campaign as measured using behavioral data from the party’s smartphone application. Survey data reveals that giving voice also increases other margins of campaign effort as well as perceived voice. Our evidence highlights the importance of voice for increasing political engagement.

@article{hager2025voice,
  author  = {Hager, Anselm and Hensel, Lukas and Roth, Christopher and Stegmann, Andreas},
  title   = {{Voice and Political Engagement: Evidence from a Field Experiment}},
  journal = {Review of Economics and Statistics},
  volume  = {107},
  number  = {4},
  pages   = {1149--1158},
  year    = {2025}
}

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 activists’ political careers. We find no effect of the treatments on activists’ intended and actual canvassing behaviour. The null finding holds despite a successful manipulation check and replication study, high statistical power, a natural field setting, and an unobtrusive measurement strategy. Using an expert survey, we show that the null finding shifted Bayesian posterior beliefs about the treatment’s effectiveness toward zero. The evidence thus casts doubt on two popular hypothesized instrumental drivers of political activism – voter persuasion and career concerns – and points toward expressive benefits as more plausible motives.

@article{hager2025political,
  author  = {Hager, Anselm and Hensel, Lukas and Hermle, Johannes and Roth, Christopher},
  title   = {{Political Activists are Not Driven by Instrumental Motives}},
  journal = {British Journal of Political Science},
  volume  = {55},
  pages   = {e88},
  year    = {2025}
}

How does a citizen’s decision to participate in political activism depend on the participation of others? We conduct a nationwide 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 information about the canvassing intentions of their peers. When learning that more peers participate in canvassing than previously believed, canvassers significantly reduce both their canvassing intentions and behaviour. An additional survey among party supporters underscores the importance of free-riding motives and reveals that there is strong heterogeneity in motives underlying supporters’ behavioural responses.

@article{hager2023political,
  author  = {Hager, Anselm and Hensel, Lukas and Hermle, Johannes and Roth, Christopher},
  title   = {{Political Activists as Free-Riders}},
  journal = {The Economic Journal},
  volume  = {133},
  pages   = {2068--2084},
  year    = {2023}
}

Many social movements face fierce resistance in the form of a countermovement. Therefore, when deciding to become politically active, a movement supporter has to consider both her own movement’s activity and that of the opponent. This paper studies the decision of a movement supporter to attend a protest when faced with a counterprotest. We implement two field experiments among supporters of a right- and left-leaning movement ahead of two protest–counterprotest interactions in Germany. Supporters were exposed to low or high official estimates about their own and the opposing group’s turnout. We find that the size of the opposing group has no effect on supporters’ protest intentions. However, as the own protest gets larger, supporters of the right-leaning movement become less while supporters of the left-leaning movement become more willing to protest. We argue that the difference is best explained by stronger social motives on the political left.

@article{hager2022group,
  author  = {Hager, Anselm and Hensel, Lukas and Hermle, Johannes and Roth, Christopher},
  title   = {{Group Size and Protest Mobilization across Movements and Countermovements}},
  journal = {American Political Science Review},
  volume  = {116},
  number  = {3},
  pages   = {1051--1066},
  year    = {2022}
}

We conducted a large-scale survey covering 58 countries and over 100,000 respondents between late March and early April 2020 to study beliefs and attitudes towards citizens’ and governments’ responses at the onset of the COVID-19 pandemic. Most respondents reported holding normative beliefs in support of COVID-19 containment measures, as well as high rates of adherence to these measures. They also believed that their government and their country’s citizens were not doing enough and underestimated the degree to which others in their country supported strong behavioral and policy responses to the pandemic. Normative beliefs were strongly associated with adherence, as well as beliefs about others’ and the government’s response. Lockdowns were associated with greater optimism about others’ and the government’s response, and improvements in measures of perceived mental well-being; these effects tended to be larger for those with stronger normative beliefs. Our findings highlight how social norms can arise quickly and effectively to support cooperation at a global scale.

@article{caria2022global,
  author  = {Caria, Stefano and Fetzer, Thiemo and Fiorin, Stefano and Hensel, Lukas and Witte, Marc and others},
  title   = {{Global Behaviors, Perceptions, and the Emergence of Social Norms at the Onset of the COVID-19 Pandemic}},
  journal = {Journal of Economic Behavior and Organization},
  volume  = {193},
  pages   = {473--496},
  year    = {2022}
}

We provide one of the first systematic assessments of the development and determinants of economic anxiety at the onset of the coronavirus pandemic. Using a global data set on internet searches and two representative surveys from the United States, we document a substantial increase in economic anxiety during and after the arrival of the coronavirus. We also document a large dispersion in beliefs about the pandemic risk factors of the coronavirus and demonstrate that these beliefs causally affect individuals’ economic anxieties. Finally, we show that individuals’ mental models of infectious disease spread understate nonlinear growth and shape the extent of economic anxiety.

@article{fetzer2021coronavirus,
  author  = {Fetzer, Thiemo and Hensel, Lukas and Hermle, Johannes and Roth, Christopher},
  title   = {{Coronavirus Perceptions and Economic Anxiety}},
  journal = {Review of Economics and Statistics},
  volume  = {103},
  number  = {5},
  pages   = {968--978},
  year    = {2021}
}

@article{hager2021does,
  author  = {Hager, Anselm and Hensel, Lukas and Hermle, Johannes and Roth, Christopher},
  title   = {{Does Party Competition Affect Political Activism?}},
  journal = {The Journal of Politics},
  volume  = {83},
  number  = {4},
  pages   = {1681--1694},
  year    = {2021}
}

We examine how income shocks affect the suicide rate in Indonesia. We use a difference-in-differences approach, exploiting the cash transfer’s nationwide rollout, and corroborate the findings using a randomized experiment. Our estimates show that the cash transfers reduce the yearly suicide rate by 0.36 per 100,000 people, corresponding to an 18% decrease. Moreover, a different type of income shock, variability in agricultural productivity, also affects the suicide rate. The cash transfer program reduces the causal impact of the agricultural productivity shocks, suggesting an important role for policy interventions. Finally, we provide evidence for depression as a psychological mechanism.

@article{christian2019income,
  author  = {Christian, Cornelius and Hensel, Lukas and Roth, Christopher},
  title   = {{Income Shocks and Suicides: Causal Evidence From Indonesia}},
  journal = {Review of Economics and Statistics},
  volume  = {101},
  number  = {5},
  pages   = {905--920},
  year    = {2019}
}