Publications

Schools under Mandatory Testing Can Mitigate the Spread of SARS-CoV-2

Joint with Ingo Isphording, Reyn van Ewijk and Nico Pestel

2022, PNAS

We use event study models based on staggered summer vacations in Germany to estimate the effect of school re-openings after the summer of 2021 on the spread of SARS-CoV-2. Estimations are based on daily counts of confirmed coronavirus infections across all 401 German counties. A central anti-pandemic measure in German schools included mandatory rapid testing multiple times per week. Our results are consistent with mandatory testing contributing to the containment of the viral spread. We find a short-term increase in infection rates right after summer breaks, indicating the uncovering of otherwise undetected (asymptomatic) cases through the testing. After a period of about two weeks after school re-openings, the growth of case numbers is smaller in states which re-opened schools compared to the control group of states still in summer break. The results show a similar pattern for older age groups as well, arguably as a result of detected clusters through the school testing. This means that under certain conditions open schools can play a role in containing the spread of the virus. Our results suggest that closing schools as a means to reduce infections may have unintended consequences by giving up surveillance and should be considered only as a last resort.

For a German summary see IZA Standpunkt 101 

Media coverage in Welt and Focus 


Is large-scale rapid CoV-2 testing a substitute for lockdowns?

Joint with René Glawion, Peter G. Kremsner, Timo Mitze, Gernot J. Müller, Dominik Papies, Felix Schulz and Klaus Wälde

2022, PLOS ONE

Various forms of contact restrictions have been adopted in response to the Covid-19 pandemic. Around February 2021, rapid testing appeared as a new policy instrument. Some claim it may serve as a substitute for contact restrictions. We study the strength of this argument by evaluating the effects of a unique policy experiment: In March and April 2021, the city of Tübingen set up a testing scheme while relaxing contact restrictions. We compare case rates in Tübingen county to an appropriately identified control unit. We employ the synthetic control method. We base interpretations of our findings on an extended SEIR model. The experiment led to an increase in the reported case rate. This increase is robust across alternative statistical specifications. This is also due to more testing leading initially to more reported cases. An epidemiological model that corrects for ‘more cases due to more testing’ and ‘reduced testing and reporting during the Easter holiday’ confirms that the overall effect of the experiment led to more infections. The number of rapid tests were not sufficiently high in this experiment to compensate for more contacts and thereby infections caused by relaxing contact restrictions.

Work in progress

The Effect of an Editorial Connection in the Peer Review Process of Economic Journals

This study investigates whether economic scholars with a connection to an editor have an advantage. I use panel data and variation in the timing of editorial appointments to estimate connection effects. The findings suggest that editorial connections boost productivity by 15% during the years of the connected editor’s appointment. These effects are likely due to editorial knowledge spillovers as I document productivity increases also in other similar journals. This study is essential to better understand the integrity and fairness of the publication process by examining the potential biases introduced by editorial connections.



Dissertation Paths: Advisors and Students in the Economics Ph.D. Production Function, joint with Joshua Angrist

The majority of graduate students in economics - even those from elite programs  - do not publish any papers in the decade after their graduation. This study intends to investigate a  graduate economics education production function where the principal inputs are faculty advisors to graduate students, and the outputs are students’ productivity in paper publications.  Specifically, we examine the following questions: Does the faculty composition, with respect to available advisors’ advising experience and research skill, matter for PhD students research productivity? How big is the advisor-student apprenticeship effect and is advisor-student research field affinity an important student success determinant? How is advisory load and student success distributed across advisors? We hope to analyze potentially causal relationships between the productivity of Ph.D. graduates and certain attributes of their advisors. The analyses will be based on substantial data-collecting efforts that combine dissertation data from ProQuest as well as publication information from EconLit and Web of Science. They account for over 10000 Ph.D. students who completed their program from 1989 to 2020. Controlling for year fixed effects and department fixed effects, we regress graduation cohort size and graduation cohort publication rate in year 0-5 after graduation against the number of productive advising faculty 2-4 years prior to graduation.  By answering those questions, we hope to find insights to productivity improvements in faculty training for the economics department.


Interdisciplinary Research in Economics, joint with Tristan Stahl

Interdisciplinarity is seen as a desirable aspect of research projects that is often promoted by research institutions. However, our study reveals that interdisciplinary research projects are associated with lower citation counts and worse journal placements. These findings show that there is a misalignment between the goals of  research institutions and researchers, because researchers need highly ranked publications for their promotions. We study a sample of over 13,000 research articles published in economics journals in 2011 and 2012 and present three novel measures of interdisciplinarity. We conduct a Specification Curve (SC) Analysis, which allows for a transparent discussion of data analytic decisions and the visualization of their impact on effect sizes. Furthermore, we find that conducting interdisciplinary research is not a high-risk, high-reward endeavor but instead: that citation counts to interdisciplinary articles do not catch up with those of non-interdisciplinary articles over time.  Our results are not due to a false classification of cross disciplinary articles as having low interdisciplinarity, as shown by a robustness exercise where we include business articles and we show that effect sizes are more emphasized for high-ability researchers.  The results of this study may be used to better align researcher and institutional goals.


Changes in health and efficiency outcomes induced by electronic dispatch protocols, joint with Reyn van Ewijk

While much is known about emergency health care provision in hospitals, research about the time before patients enter hospitals is scarce. Using the introduction of electronic dispatch protocols (EDP), a software for supporting dispatchers in structuring and standardizing their calls, this research evaluates potential benefits of EDP software. We have dispatch center specific data on emergency call and vehicle allocation and registry data on death causes at our disposal. With a staggered differences in differences approach with county and time fixed effects and allowing for county specific time trends, we find that EDP software  (i) increases the average time until an emergency vehicle gets alarmed by 4.3% and reduces the number of extreme alarm times (ii) does lead to more false positive and fewer false negative alarms (iii) does lead to a significant reduction of fatalities from acute myocardial infarction. Taken together, our results suggest that the usage of electronic dispatch protocols has a big impact on the functioning of the emergency system, resulting in fewer deaths from emergencies that crucially rely on a fast treatment.