Randomized experiments as the bronze standard

In this paper, the strengths and weakneses of randomized field experiments are discussed. Although it seems to be common knowledge that random assignment balances experimental and control groups on all confounders, other features of randomized field experiments are somewhat less appreciated. These include the role of random assignment in statistical inference and representations of the mechanisms by which the treatment has its impact. Randomized experiments also have important limitations and are subject to the fidelity with which they are implemented. In the end, randomized field experiments are still the best way to estimate causal effects, but are a considerable distance from perfection.     

刑事技术专业实践教学模式论

随着现代科学技术的发展,刑事科学技术在侦查破案中的作用愈来愈重要。公安院校应更新观念,加强刑事技术专业的实验实践教学,从而培养出政治合格、科学素养高、适应能力强、理论基础扎实、实践能力和专业技能较强的刑事技术专业人才。     

Testing hot-spots police patrols against no-treatment controls: Temporal and spatial deterrence effects in the London Underground experiment

Our understanding of causality and effect size in randomized field experiments is challenged by variations in levels of baseline treatment dosage in control groups across experiments testing similar treatments. The clearest design is to compare treated cases with no-treatment controls in a sample that lacks any prior treatment at baseline. We applied that strategy in a randomized test of hot-spots police patrols on the previously never-patrolled, track-level platforms of the London Underground (LU). In a pretest–posttest, control-group design, we randomly assigned 57 of the LU's 115 highest crime platforms to receive foot patrol by officers in 15-minute doses, 4 times per day, during 8-hour shifts on 4 days a week for 6 months. The effect of 23,272 police arrivals at the treatment hot spots over 26 weeks was to reduce public calls for service by 21 percent on treated platforms relative to controls, primarily when police were absent (97 percent of the measured effect). This effect was six times larger than the mean standardized effect size found in the leading systematic review. This finding provides a benchmark against the baseline counterfactual of no patrol in hot spots, with strong evidence of residual deterrence and no evidence of local displacement.     

What is the impact of bilingual communication to mobilize Latinos? Exploratory evidence from experiments in New Jersey,North Carolina,and Virginia

Should materials aimed at increasing Latino voter turnout be in English or bilingual? Credible, theoretical arguments can be made both ways: bilingual materials may be more effective if signaling cultural awareness or less effective if seen as pandering. We tested these competing hypotheses with two rounds of randomized field experiments in New Jersey and Virginia in 2015, and North Carolina in 2016. While some GOTV experiments have used bilingual mailers, previous scholarship has not tested whether bilingual mailers are more effective than English-language materials. In the 2015 elections, both treatments increased turnout, and the monolingual English version was more effective at increasing turnout than the bilingual version. These results are replicated in the high salience 2016 election in North Carolina. These results indicate that further research is needed about bilingual communication across political and demographic contexts and about how household composition may condition the effects of bilingual communication.     

Terrorist attacks and Europeans’ attitudes towards immigrants: An experimental approach

Over the past several years an increasing number of terrorist attacks committed in the name of Islam and targeting civilians have taken place in many Western democracies, calling for more research on the impact of these exogenous events on citizens’ attitudes towards immigrants. Using a quasi-experimental design, this study examines the short-term effect of the Paris attacks of the night of 13 November 2015 on the attitudes towards European Union (EU) and non-EU immigrants across 28 EU countries. Employing Eurobarometer 84.3 survey data collected in 28 European countries between 7 and 17 November 2015, the design allows the testing of individual attitudes before and after the Paris attacks and the spillover effects of this event in all European countries. It is found that the Paris attacks had a significant negative effect on attitudes towards immigrants, especially among educated and left-wing individuals. Moreover, the negative effect was stronger in countries where the national political-ideological climate was more positive towards immigrants. These findings are explained by theorising that first emotional reactions to the attack are the results of coping mechanisms whereby individuals are confronted with disconfirmation/confirmation of their previous beliefs: individuals who experience stronger stereotype disconfirmation are the most negatively affected by the terrorist attack. Overall, the study holds important implications for understanding the short-term impact of terrorist attacks on public attitudes towards immigrants.     

High Performance Expectations: Concept and Causes

Employees contribute more when they are aware of their leaders’ high performance expectations (HPE), but how can leaders successfully convey HPE? Here it is argued that both transformational and transactional leadership behaviors involve goal-setting, which can affect employee-perceived HPE. Using a leadership training field experiment with 3,730 employees nested in 471 organizations, the findings support that training in transformational, transactional and combination leadership training significantly increased employees’ HPE relative to a control group. Furthermore, transformational leadership and pecuniary rewards seem to be important mechanisms. This implies that public leaders can affect HPE through leadership and thus potentially organizational performance.     

Do Online Ads Influence Vote Choice?

Do online ads influence vote choice? We partner with a German party to evaluate the effectiveness of online ads using a cluster-randomized experiment. During the 2016 Berlin state election, 189 postal districts were randomly assigned to (a) emotional ads; (b) factual ads; or (c) no ads. Analyzing electoral results at the postal district level, we find that the overall campaign weakly increased the party’s vote share by 0.7 percentage points (p-value = 0.155). We also estimate a negative effect of the campaign on the vote share of the party’s main competitors of 1.4 percentage points (p-value = 0.094). Turning to the mechanism of persuasion, we find that the factual ads, if anything, fared slightly better than the emotional ads. Our evidence thus provides tentative support that online ads positively affect vote choice.     

International influence in democratic transitions: a case comparison of Spain and Greece

Examining the impact of the international system on the domestic system in countries in the process of democratisation, the article seeks to account for the relation between regime-initiated democratic transitions and the international factor, taking two case studies of the way the international factor interacted with the decisions and tactics of regime and opposition elites. The first is the Spanish exemplary reforma pactada of 1977; the second is the much less studied case of the short-lived and aborted “Markezinis experiment” in Greece in 1973, the failure of which has been blamed by its protagonist on external- mainly American- opposition.     

A field experiment on ethnic discrimination among local Swedish public officials

This study presents an innovative field experiment exploring ethnic discrimination in contacts between local public officials and members of Swedish society. Using a correspondence study design, fictitious individuals with Arabic- and Swedish-sounding names contacted Swedish municipalities via email, asking questions about access to preschools. The findings indicate disadvantageous treatment of individuals with Arabic-sounding names in terms of the informal tone of the replies, as Swedish-sounding names were replied to in a friendlier, more welcoming way. Regarding the more formal aspects of the emails – i.e., whether they were replied to at all and the questions posed were directly answered – no statistically significant signs of discrimination emerge (although differences were of some substantial size, to the disadvantage of Arabic-sounding names). Still, informal disadvantageous treatment is sufficient cause for concern and noteworthy in the case of Sweden, considering its reputation as being egalitarian, immigration friendly and democratically well functioning.     

Attitudes toward Consent-Based and Non-Consent-Based International Law in a Regional Power Context

International legal scholars have identified and argued for and against new forms of non-consent-based international law. We study variation in Brazilian public opinion about adherence to international law created in three different ways: through a consent-based multilateral treaty, by the U.N. Security Council with the participation of Brazil, and by the U.N. Security Council without the participation of Brazil. Information that Brazil has participated in creating the international legal obligation through a multilateral treaty or membership on the Security Council yields levels of support for adherence to the legal obligation that are similar to those found when the origins of the legal obligation are generic. Information that the international legal obligation was created without Brazil’s participation, on the other hand, results in reduced support for compliance. This difference, which is particularly concentrated among highly educated respondents, is not driven by reduced concerns about reputational consequences or sanctions. Our results suggest that the increased use of non-consent-based forms of international law might be challenged by a lack of public support for compliance.