Sascha Riaz

Publications

1. Temperature and Aggression Revisited: Evidence from 1 Million Amateur Football Matches (with Maurice Baudet von Gersdorff and Heike Klüver). Forthcoming, PNAS Nexus.
   [Abstract]

   A large body of research documents a positive relationship between temperature and human aggression, underpinning projections of increased conflict in a warming climate. However, most prior evidence relies on laboratory experiments with convenience samples or on crime records, both of which are limited in their generalizability to everyday social interactions. To isolate the effect of temperature in a standardized, real-world social environment, we analyze ∼1 million amateur football matches played across Germany and study aggression among more than one million amateur players. Comparing matches played at the same venue within the same league and season, and adjusting for referee and team differences, we find a precisely estimated inverted-U relationship between temperature and player aggression: disciplinary cards (issued by referees for fouls and misconduct) increase with temperature up to ∼13 °C but decline thereafter. Matches played under extreme heat show a 15% reduction in disciplinary actions relative to the sample mean. Our results contribute to the temperature–aggression literature: in line with affect-based accounts of aggression, moderate warmth may increase irritability and arousal; however, to the extent that aggressive behavior requires physical engagement, it may decline at extreme temperatures.
2. Null by Design: Statistical Dilution in Immigration-Crime Research. Forthcoming, British Journal of Political Science.
   [Abstract]

   Recent research documents that many research designs in the social sciences are underpowered: they can detect only extremely large -- often implausible -- effects. I show that this problem is structural in the workhorse approach to studying the immigration-crime link: regressing changes in aggregate crime rates on exogenous shifts in local immigrant shares. While this design may identify changes in native criminal behavior, I demonstrate that it is largely uninformative regarding the difference in crime propensities between immigrants and natives. Because immigrants typically comprise a small fraction of the population, even large group-level differences are mechanically diluted. I formalize the minimum detectable gap -- the smallest immigrant-native crime difference these regressions can reliably distinguish from zero given standard design parameters. Using Monte Carlo simulations calibrated to real-world immigration and crime data, I demonstrate that conventional designs only achieve adequate statistical power with implausibly large crime differentials and extreme immigration shocks.
3. Shielding Voters? How Partisanship Shapes the Placement of Refugee Housing Facilities (with Jeremy Ferwerda). Forthcoming, Journal of Politics.
   [Abstract]

   Many European countries have adopted dispersal policies to proportionally allocate refugees across their territories. In this paper, we draw on a novel dataset of refugee housing locations during the Syrian refugee crisis in Germany to assess how a prominent dispersal policy was implemented in practice. Although the policy was designed to distribute refugees according to population and tax revenue, our results show that county governments differentially placed refugee housing in municipalities that favored political opponents. Given the center-right's predominant control over county councils, this resulted in a concentration of housing in left-leaning municipalities. Our findings illustrate how partisanship can distort ostensibly bureaucratic humanitarian policies, with downstream implications for refugee integration. In addition, these findings suggest that researchers examining the relationship between refugee contact and political behavior should be cautious when assuming that local exposure is as-if randomly assigned in settings where local governments exercise authority over refugee dispersal policies.
4. Limited Backlash? Assessing the Geographic Scope of Electoral Responses to Refugees (with Jeremy Ferwerda). Forthcoming, Political Science Research and Methods.
   [Abstract]

   Recent research suggests that local exposure to refugees does not increase support for far-right parties. We challenge this null result by drawing on granular data from Berlin in the wake of the Syrian refugee crisis. While prior work in the German context has generally assumed that refugee exposure is exogenous at the local level, we demonstrate that refugee housing was disproportionately concentrated in neighborhoods with young, non-citizen residents. To address this selection bias, we harmonize in-person and mail-in precinct boundaries across elections and implement a difference-in-differences design with synthetic precincts. We find that localized exposure to refugee housing did increase support for the far-right in the 2017 federal elections. However, this backlash is geographically narrow in scope. Our findings nuance prior research by demonstrating that even if sociotropic concerns dominate electoral responses to the refugee crisis, voters' responses are consistent with group threat theory at the local level.
5. Racial Threat in Public Social Spaces (with Tobias Roemer). Forthcoming, Journal of Politics.
   [Abstract]

   What are the electoral effects of repeated exposure to ethnic diversity in public social spaces? We study this question in the context of public swimming pools in Germany, where intergroup relations have become increasingly politicized. Our analysis combines (i) information on the geolocation of all public pools in Germany, (ii) a panel survey of more than 240,000 voters, and (iii) new survey data on threat perceptions in public pools. Using a difference-in-differences design that leverages the seasonality of outdoor swimming pools for causal identification, we estimate that exposure to ethnic diversity in public pools increases far-right support by about 0.8 percentage points. Additional panel analyses suggest that these results are driven by an increase in the issue salience of immigration relative to taxes and redistribution. Our findings lend credence to the racial threat hypothesis in politicized public social spaces that do not meet Allport's conditions for positive intergroup contact.
6. Anti-immigrant Bias in the Choice between Punitive and Rehabilitative Justice (with Maik Hamjediers). Forthcoming, British Journal of Political Science.
   [Abstract]

   We study bias in judicial authorities' efforts to rehabilitate and reintegrate immigrant offenders into society. Our empirical strategy leverages a distinctive feature of the German criminal code: the optional application of rehabilitative juvenile criminal law or punitive general criminal law for 18-20-year-old offenders, based on a subjective assessment of offenders' psychological 'maturity' by judges. Drawing on complete records of 792,000 court hearings between 2009 and 2018, we show that immigrant offenders are about ten percentage points less likely to be sentenced under juvenile law compared to natives convicted for the same crime. The immigrant-native gap in rehabilitative justice correlates with anti-immigrant sentiment across space and has spiked in recent years, suggesting a link between the salience of group-based identities and judicial decision-making. Our findings raise concerns about equal legal treatment and highlight that biases in the application of rehabilitative justice may contribute to higher recidivism rates among immigrant offenders.
7. The Gendered Persistence of Authoritarian Indoctrination (with Nourhan Elsayed, Hanno Hilbig, and Daniel Ziblatt). Forthcoming, British Journal of Political Science.
   [Abstract]

   A large literature has studied the effects of socialization under authoritarianism on political attitudes. In this research note, we extend this literature by demonstrating striking gender disparities in the post-transition persistence of these effects. We study the case of authoritarian indoctrination in the German Democratic Republic (GDR) using a regression kink design for causal identification. First, we draw on a unique survey fielded right before reunification to show that education under authoritarianism substantially reduced support for democratic capitalism and reunification with the West. In the second step, we triangulate multiple contemporary data sources to trace the persistence of these effects over time. More than two decades after the fall of the GDR, the attitudinal effects of authoritarian socialization persist only among men, but not women. Our results highlight considerable heterogeneity in the persistence of authoritarian legacies, raising critical questions about post-authoritarian 're-socialization' and gendered adaptability.
8. Do Autocrats Respond to Citizen Demands? Petitions and Housing Construction in the GDR (with Hans Lueders and Hanno Hilbig). Forthcoming, Comparative Political Studies.
   [Abstract]

   Citizens in authoritarian regimes frequently communicate grievances to the government. While there is some evidence that governments respond to such petitions, little is known about the nature of this responsiveness: can petitions influence resource allocation and yield tangible improvements to citizens' livelihoods? To answer this question, we assemble a novel panel of housing-related petitions to the government of the German Democratic Republic (GDR) and all housing constructed between 1945-1989. Exploiting the timing of the largest housing program in 1971, we employ a difference-in-differences approach to show that construction was targeted at regions with higher rates of petitioning. We then use a variance decomposition method to benchmark petitions against objective indicators of housing need. Our results suggest that petitions allow citizens to meaningfully influence the allocation of public resources. The paper contributes to nascent scholarship on responsiveness in non-democratic regimes by linking responsiveness to tangible improvements in citizens' livelihoods.
9. After the Genocide: Proximity to Victims and Support for Punishing Ingroup Crimes (with Volha Charnysh). Forthcoming, Comparative Political Studies.
   [Abstract]

   What explains divergent transitional justice preferences among political elites after genocide? We argue that elite preferences vary with their proximity to the victimized group. Individuals who know the victims personally and/or have witnessed violence against them may be more likely to support punishing the perpetrators, possibly because they experience collective guilt. We support this argument using an original biographical dataset on the members of the West German parliament, linking their location and experiences during the Third Reich to free roll-call votes on extending the statute of limitations for murder in 1965-69. We find that proximity to synagogues, particularly those attacked in November 1938, predicts support for extending the statute, conditional on party, state, mandate type, denomination, and a host of personal attributes. We also find significantly lower support for extending the statute among former NSDAP members. Our findings highlight the importance of bystander experiences in shaping support for retributive justice.
10. Local Newspaper Decline and Political Polarization - Evidence from a Multi-Party Setting (with Fabio Ellger, Hanno Hilbig, and Philipp Tillmann). British Journal of Political Science, 54(4):1256-1275.
    [Abstract]

    How does the decline of traditional news outlets affect political polarization? We provide novel evidence on this question by examining the link between local newspaper exits, media consumption, and electoral behavior in a multiparty setting. Our empirical analysis combines a unique panel of all German local newspapers between 1980 and 2009, electoral returns, and an annual media consumption survey of more than 670,000 respondents. Using a difference-in-differences design, we demonstrate that local newspaper exits increase electoral polarization. Additional analyses point to changes in media consumption as the underlying mechanism driving this result: following local news exits, consumers substitute local news with national tabloid news. Our findings extend prior results in the US context to a multiparty setting and shed new light on the causal chain running from changing local news landscapes to electoral behavior.
11. Out-group Threat and Xenophobic Hate Crimes (with Daniel Bischof and Markus Wagner). Journal of Politics, 86(4): 1147-1161.
    [Abstract]

    This study examines the relationship between crimes attributed to immigrants and hate crimes against refugees at the local level. We argue that local crime events can lead natives to engage in vicarious retribution against uninvolved out-group members - refugees in our setting. Our empirical analysis relies on fine-grained geo-coded data on more than 9,400 hate crimes and 17,600 immigrant-attributed crime events that occurred in Germany between 2015 and 2019. Using a regression discontinuity in time design, we show that the daily probability of a hate crime against refugees rises sharply in the immediate aftermath of an immigrant-attributed crime event in a local community. Additional analyses suggest that immigrant-attributed crime acts as an emotional 'trigger', particularly in areas with strong radical-right support and recent demographic change. Our findings imply that individual, commonplace crime incidents can give rise to inter-group conflict dynamics at the local level.
12. Does Inequality Foster Xenophobia? Evidence from the German Refugee Crisis. Journal of Ethnic and Migration Studies, 50(2): 359-378.
    [Abstract]

    Why does immigration trigger xenophobic backlash in some regions but not in others? This study focuses on economic inequality as a moderator of backlash against immigration. Drawing on prior cross-national work, I argue that inequality fosters a sense of relative deprivation among natives, increases incentives for national identification, and thereby amplifies xenophobic backlash against immigration. I test this argument in Germany, which experienced an unprecedented influx of refugees starting in 2015. My empirical analysis combines complete tax registry data for about 40 million households with geocoded information on xenophobic hate crimes. Using a difference-in-differences approach, I find that the increase in hate crimes following the refugee inflow was significantly stronger in high-inequality localities. In addition, I provide survey-based evidence that local economic inequality increases nationalism among natives. My findings shed new light on the connection between rising levels of economic inequality and xenophobia across Western democracies.
13. Refugee Labor Market Access Increases Support for Immigration (with Anselm Hager and Hanno Hilbig). Comparative Political Studies, 57(5): 749-777.
    [Abstract]

    Does the economic integration of refugees affect public attitudes toward migration? We assess this pertinent question by examining a policy change in Germany, where the government significantly eased labor market access for refugees in the majority of the country. Using administrative employment data, we show that the policy led to a substantial increase in refugee employment, while natives' wages and employment rates remained unaffected. The policy also had a positive effect on natives' attitudes toward migration. Voters exposed to more refugees in the labor market were two percentage points more likely to vote for pro-migration parties across both state and federal elections. Additional survey analyses suggest that our results are driven by positive native-refugee interactions in the workplace.
14. Natural Disasters and Green Party Support (with Hanno Hilbig). Journal of Politics, 86(1): 241-256.
    [Abstract]

    A growing literature shows that extreme weather events induce pro-environment attitudes. We examine the political effects of a severe flood shortly before the 2021 German federal election. Drawing on about 600,000 survey responses and electoral data, we assess how flooding affected (i) the perceived salience of climate change, (ii) self-reported Green Party support, and (iii) Green Party voting in federal elections. We find that even severe local flooding had little to no effect on these outcomes. Additional evidence supports two mechanisms underlying this finding: nationwide rather than local effects of severe disasters, and voter demands for disaster relief rather than climate change prevention. We test the former mechanism using a regression discontinuity design and find that the flood increased nationwide Green Party support, although this effect persists for only two weeks. Our results shed new light on the precise duration and geographic scope of the political effects of natural disasters.
15. War and Nationalism: How WW1 battle deaths fueled civilians' support for the Nazi Party (with Felix Haass, Alexander De Juan, Carlo Koos, and Thomas Tichelbaecker). American Political Science Review, 118(1): 144-162.
    [Abstract]

    Can wars breed nationalism? We argue that civilians' indirect exposure to war fatalities can trigger psychological processes that increase identification with their nation and ultimately strengthen support for nationalist parties. We test this argument in the context of the rise of the Nazi Party after World War 1. To measure localized war exposure, we machine-coded information on all 8.6 million German soldiers who were wounded or died in WW1. Our empirical strategy leverages battlefield dynamics that cause plausibly exogenous variation in the county-level casualty fatality rate - the share of dead soldiers among all casualties. We find that throughout the interwar period, electoral support for right-wing nationalist parties, including the Nazi Party, was 2.6 percentage points higher in counties with above-median casualty fatality rates. Consistent with our proposed mechanism, we find that this effect was driven by civilians rather than veterans and areas with a preexisting tradition of collective war commemoration.
16. Local News Monopolies Increase Misperceptions about Immigration (with Hanno Hilbig). Journal of Ethnic and Migration Studies, 49(17): 4536-4558.
    [Abstract]

    We examine how local news monopolies affect misperceptions about the size of the immigrant population in Germany. We propose a theoretical framework in which heterogeneous information from different local news outlets diffuses through social interactions. We posit that indirect exposure to information from multiple sources leads to more accurate beliefs in competitive markets. To causally identify the effect of local news monopolies on misperceptions, we exploit overlapping newspaper coverage areas as a source of exogenous variation in the number of available outlets. We estimate that local news monopolies increase misperceptions about the size of the local immigrant population by about four percentage points. We demonstrate that the effect of media monopolies hinges on social interactions. For individuals with fewer close social contacts, misperceptions remain unaffected by local news monopolies. Our results suggest that consolidation in the market for news decreases constituents' knowledge about critical policy issues.
17. Freedom of Movement Restrictions Inhibit the Psychological Integration of Refugees (with Hanno Hilbig). Journal of Politics, 84(4): 2288-2293.
    [Abstract]

    How do freedom of movement restrictions affect refugee integration? While a growing body of research studies the initial allocation of refugees, there is little causal evidence on subsequent policies that restrict residential mobility. We study a contentious law in Germany, which barred newly arrived refugees from relocating to a location different from the one they were assigned to. To identify the causal effect of the movement restriction on integration, we utilize a sharp date cutoff that governs whether refugees are affected by the policy. We demonstrate that restricting freedom of movement had pronounced negative effects on refugees' sense of belonging in Germany, while increasing identification with their home countries. In addition, the policy decreased social engagement, but had no detectable effects on contact with natives or co-ethnics. We argue that detrimental effects stem from the fact that discriminatory policies send a negative signal about the inclusiveness of the host society.

Working Papers

• Revisiting History, Reshaping Memory: The Effects of Confronting In-Group Atrocities (with Alexander De Juan, Julian Voß, and Anton Peez). Conditionally accepted, American Journal of Political Science.
  [Abstract]

  How do voters react to challenges of collective memories? We study the controversial 'Wehrmacht exhibition' (1995–1999), which exposed the German public to graphic evidence challenging the 'myth of the clean Wehrmacht' - the false narrative that only the SS, not the military, systematically committed war crimes and perpetrated the Holocaust. To study the exhibition's effects, we leverage survey data of over 830,000 voters in a staggered difference-in-differences setup. We complement this analysis with evidence from over 1,200 letters to the editor, an original survey of Germans born around the end of WWII, and interviews with public figures who spoke at exhibition openings. We find that the exhibition triggered political backlash, particularly among the children of WWII soldiers. However, this backlash was localized and short-lived. We also show that the exhibition effectively shifted public discourse on the Wehrmacht, demonstrating that memory entrepreneurs can overturn self-serving narratives without lasting political repercussions.
• Type I Error Inflation in Unexpected Event During Survey Designs (with Joris Frese). R&R, American Journal of Political Science.
  [Abstract]

  The ‘Unexpected Event During Survey' design (UESD) leverages quasi-random timing of interviews relative to external events for causal identification. In this research note, we empirically evaluate the UESD's Type I (false positive) error rate using large-scale survey data covering 40 countries between 2002 and 2024. Based on over 42 million placebo tests, our analysis reveals that standard inferential approaches yield false positives at rates more than double the conventional 5% threshold, indicating miscalibrated p-values and potentially erroneous conclusions. We further document significant heterogeneity in this error inflation across countries, surveys, outcome variables, and model specifications. To address this, we propose a randomization-based adjustment procedure tailored to context-specific false positive rates and provide open-source software for its implementation. We illustrate our approach by replicating the two most highly cited UESD articles published in the APSR.
• Regime Loyalty During Wartime - Evidence from Nazi Germany (with Alexander De Juan, Felix Haass, and Julian Voß)
  [Abstract]

  Measuring regime support in closed autocracies is notoriously challenging due to preference falsification, state censorship, and pervasive propaganda. We introduce a novel behavioral measure of regime loyalty based on subtle expressions of allegiance in soldier obituaries published in Nazi Germany between 1939 and 1945. Our empirical analysis draws on a large-scale dataset of over one million scanned pages from roughly 160,000 newspaper issues across 260 unique local news outlets. Using Large Language Models for OCR and data labeling, we detect expressions of regime support, such as praise for Hitler, National Socialism, or the Fatherland, in approximately 600,000 obituaries. Our approach yields the first spatially and temporally granular measure of Nazi regime support during World War II. Our descriptive findings nuance the prevailing historical consensus: we find that regime loyalty began to erode immediately following the 1941 invasion of the Soviet Union, not after the Battle of Stalingrad. By contrast, militaristic rhetoric emphasizing soldiers' heroism persisted at high levels throughout the war.