Felix Hartmann

Can deliberative mini-publics strengthen democratic attitudes? We study this question using a pre-registered field intervention conducted by a non-partisan NGO in collaboration with Members of the German Bundestag. Across 17 full-day events in six constituencies, randomly sampled citizens participated in structured face-to-face deliberation with elected representatives. To estimate effects, we use a placebo design comparing participants to individuals from the same districts who report they would participate if invited. Participation increases internal and external political efficacy, willingness to engage beyond voting, and political trust, with effects of 0.26-0.53 standard deviations. Participation also reduces conspiracy thinking, though this finding is less robust. Results are consistent across different identification strategies. Exploratory analyses suggest larger effects when representatives from multiple parties are present. These findings provide causal field evidence that deliberative mini-publics can strengthen key democratic attitudes and highlight their potential to reinforce democratic foundations.

Right-wing populist parties have become a major challenge to liberal democracies worldwide. How can mainstream parties effectively counter their appeal? While prior research has focused on the drivers of populist support, much less is known about how to counter right-wing populist rhetoric. We test four communication counter-strategies that target core elements of right-wing populist appeals: (i) undermining populists’ claims to democratic credibility, (ii) promoting inclusive in-group identity to counter exclusionary narratives, (iii) highlighting their performance legitimacy, and (iv) emphasizing the procedural legitimacy of mainstream parties. Drawing on real-world party communications from social media, manifestos, and press releases, we created 170 experimental treatments (posters and social media posts varying in format and complexity) to simulate how voters encounter political messages in everyday life. In a large-scale survey experiment with over 24,000 respondents in Germany, messages undermining right-wing populists’ democratic credibility prove most effective, particularly among citizens with high initial support for such parties.

Despite decades of scholarship on protest effects, we know little about how bystanders, citizens who merely observe protests without participating, are affected by them. Understanding the impact of protest on bystanders is crucial as they constitute the silent majority whose latent support, normative beliefs, and concrete actions can make or break a movement's broader societal impact. We address this gap with a novel field experiment in Berlin, Germany, randomly routing pedestrians past (treatment) or away from control three large-scale Fridays for Future (FFF) climate strikes. Additionally, we conducted a one-month follow-up to assess the persistence of effects. We find no detectable impact on climate attitudes, vote intentions, or norm perceptions but a substantial increase in immediate donations to climate causes. These results suggest that protest is more likely to influence bystanders through immediate behavioral cues than through changes in attitudes or norms. Our findings challenge the prevailing assumption in both scholarship and public discourse that protests reshape public opinion in a direct and unmediated way, calling for renewed theorizing of protest effects that centers on observers' immediate behavioral activation rather than just opinion change mechanisms.

Recent literature has explored the impact of policy reversals on citizens’ attitudes towards the government, mostly finding negative effects. We contribute to research exploring whether scientifically supported policy updates from apolitical public authorities can mitigate negative backlash. Drawing on an information experiment conducted among 10,500 citizens in Germany, we find that inconsistent advice adversely affects perceived credibility and competence of the government and that prior trust does not influence this effect. Exposing citizens to information about the scientific process and the normalcy of changing recommendations yields a positive but insignificant effect. In a second analysis, we study the implications of this for policymaking. We analyze public health policy changes in the context of the Covid-19 crisis across 65 countries and find that incumbents who face electoral pressure indeed change their recommendations less often. Taken together, the results suggest that governments in democracies face a difficult-to-resolve trade-off between electoral support and public welfare once new, inconsistent evidence becomes available.

Survey experiments are an important tool to measure policy preferences. Researchers often rely on the random assignment of policy attribute levels to estimate different types of average marginal effects. Yet, researchers are often interested in how respondents trade-off different policy dimensions. We use a conjoint experiment administered to more than 10,000 respondents in Germany, to study preferences over personal freedoms and public welfare during the COVID-19 crisis. Using a pre-registered structural model, we estimate policy ideal points and indifference curves to assess the conditions under which citizens are willing to sacrifice freedoms in the interest of public well-being. We document broad willingness to accept restrictions on rights alongside sharp heterogeneity with respect to vaccination status. The majority of citizens are vaccinated and strongly support limitations on freedoms in response to extreme conditions—especially, when they vaccinated themselves are exempted from these limitations. The unvaccinated minority prefers no restrictions on freedoms regardless of the severity of the pandemic. These policy packages also matter for reported trust in government, in opposite ways for vaccinated and unvaccinated citizens.

By September 2021 an estimated 32% of the global population was fully vaccinated for COVID-19 but the global distribution of vaccines was extremely unequal, with 72% or more vaccinated in the ten countries with the highest vaccination rates and less than 2% in the ten countries with the lowest vaccination rates. Given that governments need to secure public support for investments in global vaccine sharing, it is important to understand the levels and drivers of public support for international vaccine solidarity. Using a factorial experiment administered to more than 10,000 online survey respondents in Germany in 2021, we demonstrate that the majority of German citizens are against global inequalities in vaccine distribution. Respondents are supportive of substantive funding amounts, on the order of the most generous contributions provided to date, though still below amounts that are likely needed for a successful global campaign. Public preferences appear largely to be driven by intrinsic concern for the welfare of global populations though are in part explained by material considerations—particularly risks of continued health threats from a failure to vaccinate globally. Strategic considerations are of more limited importance in shaping public opinion; in particular we see no evidence for free riding on contributions by other states. Finally, drawing on an additional survey experiment, we show that there is scope to use information campaigns highlighting international health externalities to augment public support for global campaigns.

Major crises regularly lead to a public debate about whether the government should be able to restrict personal freedoms in the interest of public welfare. Using a factorial survey experiment administered to more than 10,000 online survey respondents in Germany during the COVID crisis, we assess under what conditions citizens are willing to sacrifice individual civil freedoms in the interest of public well-being. Despite highly visible protests against Covid policies, we document broad willingness to accept restrictions on rights alongside sharp heterogeneity with respect to vaccination status and party identification. The majority of citizens are vaccinated and strongly support limitations on freedoms in response to extreme conditions---especially when the vaccinated themselves are exempted from these limitations. The unvaccinated minority generally prefer no restrictions on freedoms regardless of the severity of the pandemic. These policy preferences in turn matter for reported trust in government, in opposite ways for vaccinated and unvaccinated citizens.

As of early 2022 an estimated 50% of the global population is fully vaccinated for COVID-19 but the global distribution of vaccines is extremely unequal, over 85% vaccinated in the top 10 countries and below 3% in the bottom 10. Given that governments need to secure public support for investments in global vaccine sharing, it is important to understand the levels and drivers of public support for international vaccine solidarity. Using a factorial experiment administered to more than 10,000 online survey respondents in Germany, we show that global inequities are out of line with domestic German public opinion. Respondents are supportive of substantive funding amounts, on the order of the most generous contributions provided to date, though still below amounts that are likely needed for a successful global campaign. Public preferences appear largely to be driven by intrinsic concern for the welfare of global populations though are in part explained by material considerations – particularly risks of continued health threats from a failure to vaccinate globally. Strategic considerations are of more limited importance in shaping public opinion; in particular we see no evidence for free riding on contributions by other states. Finally, drawing on an additional survey experiment, we show that there is scope to use information campaigns highlighting international health externalities to augment public support for global campaigns.

Recent evidence suggests that vaccination hesitancy is too high in many countries to sustainably contain COVID-19. Using a factorial survey experiment administered to 20,500 online respondents in Germany, we assess the effectiveness of three strategies to increase vaccine uptake, namely, providing freedoms, financial remuneration, and vaccination at local doctors. Our results suggest that all three strategies can increase vaccination uptake on the order of two to three percentage points (PP) overall and five PP among the undecided. The combined effects could be as high as 13 PP for this group. The returns from different strategies vary across age groups, however, with older cohorts more responsive to local access and younger cohorts most responsive to enhanced freedoms for vaccinated citizens.