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.

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.

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.