2021, Munzert, Simon, Selb, Peter, Gohdes, Anita, Stoetzer, Lukas F., Lowe, Will

Digital contact tracing apps have been introduced globally as an instrument to contain the COVID-19 pandemic. Yet, privacy by design impedes both the evaluation of these tools and the deployment of evidence-based interventions to stimulate uptake. We combine an online panel survey with mobile tracking data to measure the actual usage of Germany's official contact tracing app and reveal higher uptake rates among respondents with an increased risk of severe illness, but lower rates among those with a heightened risk of exposure to COVID-19. Using a randomized intervention, we show that informative and motivational video messages have very limited effect on uptake. However, findings from a second intervention suggest that even small monetary incentives can strongly increase uptake and help make digital contact tracing a more effective tool.

2018-11, Selb, Peter, Munzert, Simon

2016, Herrmann, Michael, Munzert, Simon, Selb, Peter

Speculations about whether strategic voting made a difference to the outcome of an election regularly whip up the passions of pundits, party strategists, electoral reformers and scholars alike. Yet, research on strategic voting's political effect has been hampered by the scarcity of data on district level party preferences. We propose the use of Bayesian small area estimation to predict district level preferences from just a handful of survey responses per district and comparing these predictions against election results to estimate how many voters switched sides in each district. We apply the approach to estimate how many seats changed hands as a result of strategic voting at the 1997 and 2001 UK general elections. Despite similar rates of strategic voting in both elections, the number of seats that were affected was markedly greater in 1997. Interestingly, the Liberal Democrats turn out to win the most seats because of strategic voting. We also estimate how many votes went in the ‘wrong’ direction—away from otherwise viable candidates. We validate our results by using journalistic sources and compare them with previous published estimates.

2014, Shikano, Susumu, Munzert, Simon, Schübel, Thomas, Herrmann, Michael, Selb, Peter

Bei der Entwicklung der räumlichen Modelle des Parteienwettbewerbs spielt die Valenz eine wichtige Rolle. Trotz der theoretischen Relevanz bleibt die Mess- und Schätzmethode der Valenz unterentwickelt. Angesichts dieser Forschungslücke schlägt dieser Beitrag ein statistisches Modell vor, das die gleichzeitige Schätzung der Kandidatenpositionen und der Valenz ermöglicht. Ein wichtiger Vorzug dieses Modells liegt darin, dass man nur die Kandidatenbeurteilungen per Skalometer benötigt, der in den meisten Umfragedaten verfügbar ist. Dieses Modell wird auf Daten angewendet, die in Rahmen der Konstanzer Oberbürgermeisterwahl 2012 erhoben wurden.

2020, Selb, Peter, Göbel, Sascha, Lachat, Romain

We present a polling strategy to predict and analyze runoff elections using the 2017 French presidential race as an empirical case. This strategy employs rejective probability sampling to identify a small sample of polling stations that is balanced with respect to past election results. We then survey the voters’ candidate evaluations in first-round exit polls. We poststratify the voter sample to first-round election returns to account for nonresponse and coverage issues, and impute missing candidate evaluations to emulate campaign learning. Next, the votes for eliminated competitors are redistributed according to their supporters’ lower-order preferences. Finally, the predictions are validated against official results and other polls. We end with a discussion of the advantages and limitations of this approach.

2018-01-02, Ohmura, Tamaki, Bailer, Stefanie, Meißner, Peter, Selb, Peter

Research on parliamentary careers has paid little attention to variations in pre-parliamentary career patterns and their value in explaining legislators’ parliamentary success. Using sequence and cluster analysis, this article identifies typical career tracks taken by Party Animals, Local Heroes, Late Bloomers, Land Legislators, High-Flyers and Career Changers based on a comprehensive dataset of German parliamentarians’ biographies (1998–2014). The analysis confirms the role of the party as the primary career facilitator before and within parliament. Nonetheless both Career Changers and High-Flyers climb the greasy pole all the way to the national parliament without much service to the party. The former type, however, suffers from a lack of networks and experience, which is reflected in the limited career success within parliament. This article demonstrates that the use of sequence analysis on career paths offers a promising approach in distinguishing and explaining the opportunities, choices and obstacles MPs face in parliament.

2016, Selb, Peter, Munzert, Simon

This article reports on an attempt to forecast the outcome of the 2013 election to the German Bundestag. In contrast to the predominant academic approach to forecast incumbent vote shares from measures of government popularity, economic conditions and other fundamental variables, we entirely relied on data from published trial heat polls. Opposite to common practice in the news media, we did not take isolated polls as election forecasts in their own right. Instead, we used historical data to assess empirically the relationship between polls and election outcomes, and combined extrapolations from current polls in a Bayesian manner. The forecast was published one month ahead of the election. The retrospective evaluation of our method was added after the election. While our method is parsimonious and provides a large lead time, the performance at the 2013 election was underwhelming. We offer additional suggestions how the approach can be improved in future scenarios.

2020, Munzert, Simon, Selb, Peter

Self-reports of adherence to non-pharmaceutical interventions in surveys may be subject to social desirability bias. Existing questioning techniques to reduce bias are rarely used to monitor adherence. We conducted a list experiment to elicit truthful answers to the question whether respondents met friends or acquaintances and thus disregarded the social distancing norm. Our empirical findings are mixed. Using the list experiment, we estimate the prevalence of non-compliant behavior at 28%, whereas the estimate from a direct question is 22%. However, a more permissively phrased direct question included later in the survey yields an estimate of 47%. All three estimates vary consistently across social groups. Interestingly, only the list experiment reveals somewhat higher non-compliance rates among the highly educated compared to those with lower education, yet the variance of the list estimates is considerably higher. We conclude that the list experiment compared unfavorably to simpler direct measurements in our case.

2017-04, Munzert, Simon, Selb, Peter

Does the opportunity to deliver visual instead of verbal stimuli of political knowledge to respondents in web-based surveys make a difference in terms of data quality? For instance, does the presentation of visual knowledge items reduce cheating, that is, looking up the answer via the Web? And do visual and verbal stimuli capture the same underlying construct? To test whether the use of visuals to measure political knowledge effectively makes a difference, we administer a question form experiment in an online survey of the German Longitudinal Election Study. Respondents are randomly assigned to one of two question formats—visual or verbal—and are asked to solve a set of eight questions on political leaders and their offices. The instruments are validated based on nonparametric item response theory and analyses of response latency. While there is no clear evidence for cheating behavior under either of the conditions, both instruments form strong knowledge scales. Results from a regression analysis indicate that the scales provide measures of closely related but not identical concepts.

2015, Selb, Peter, Lutz, Georg

In their seminal paper, Carey and Shugart (1995) argue that electoral rules predetermine whether election campaigns are predominantly characterized by competition between parties, or among candidates within parties. In particular, electoral systems that provide weak party control over ballot access, that allow voters to express a preference vote for individual candidates, and that select candidates on the basis of the votes they earn individually are supposed to offer strong incentives for candidates to cultivate a personal vote. In this paper, we investigate Carey and Shugart's original claims about the instrumental motivations of candidates in open-ballot proportional representation (PR) elections using survey data and election statistics from the 2007 Swiss National Council elections. As opposed to previous work, we develop and employ more direct and valid measures of intra- and interparty incentives to wage personal campaigns. Our empirical results suggest that the candidates' campaign focus and expenditures are closely linked to intraparty competition, but not interparty competition. Previously used proxies of intraparty competition, such as district magnitude or the number of candidates on a party list (or ratios thereof), turn out to be but remotely related to the candidates' campaign behavior.