Research Seminars

Accurate perception of social relationships is central to human social cognition, yet little is known about how well individuals perceive incoming social ties within their natural social environments. We collected data from 3,077 adolescents across 117 classrooms and analyzed complete social networks comprising four directed relational layers—friends, best friends, enemies, and worst enemies—alongside adolescents’ predictions of who would nominate them in each layer. Across all layers, perceptual accuracy was strikingly low. Only 0.29% of students assessed all of their relationships correctly. Errors were overwhelmingly driven by underestimation: adolescents systematically failed to recognize how many peers named them, both positively and negatively. Misperception was structured rather than random. Popularity (in-degree) was strongly associated with underestimation, whereas sociability (out-degree) was associated with overestimation. These structural patterns were consistent across relational layers and error types and showed no systematic improvement with age. Together, these findings reveal robust structural asymmetries in social cognition, suggesting that young people perceive far less of their social worlds than there is.

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We study the effect of working from home (WFH) on health-related absenteeism. We draw on a monthly panel (2018–2023) of nearly 1.9 million workers insured under a major German statutory health insurance fund. Our identification strategy leverages the differential exposure to the unexpected shift to WFH in 2020, resulting in about one-quarter of German employees regularly working remotely today. Specifically, our difference-in-differences design compares sick leave take-up across workers with different WFH potential, i.e., the teleworkability of their occupation in February 2020. Our results imply a nontrivial lasting response to WFH. Compared to the pre-treatment mean, the monthly likelihood of sick leave take-up declined by 3.3% by 2023 due to a 10-percentage-point increase in WFH potential (comparable to a shift from performing and entertainment professions to media documentation and information services). These effects are driven by reductions in respiratory infections and musculoskeletal disorders, such as back pain. The response reflects not only behavioral changes in sick leave take-up, but also genuine health improvements.

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We study how secondary markets for durable goods interact with consumers’ social-responsibility motives to mitigate environmentally harmful new production. On the positive side, secondary markets may allow responsible consumers to acquire used goods that would otherwise be discarded, reducing premature waste. On the negative side, secondary markets introduce two major harmful forces. First, the possibility of buying used goods and thereby causing less harm can raise the demand of responsible consumers, often increasing the production necessary to serve the market. Second, said demand can increase the price of used goods, encouraging purchases of new goods. These forces imply that if used goods have positive private consumption value, then secondary markets always erode the benefits of social responsibility. If, instead, used goods may have negative private value, then secondary markets can enhance or erode the benefits of social responsibility.

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Germany was the first country worldwide to introduce a structured reimbursement pathway for digital therapeutics (DiGA), effectively allowing physicians to prescribe smartphone apps covered by statutory health insurance. In this seminar, Simon Reif presents recent research evaluating whether this pioneering regulation successfully incentivized innovation in the digital health market.  Using high-frequency data from the Apple App Store and synthetic control methods, the study analyzes the market entry of health apps following the policy's introduction. The findings reveal a significant increase in the number of German-language digital therapeutics; however, this quantity did not translate into a broader diversity of medical conditions treated. Furthermore, the surge was largely driven by apps that monetize patient data for advertising rather than high-quality applications backed by scientific evidence. The presentation will discuss the implications of these results for designing policy that balances market incentives with patient privacy and care quality.

Teaser: Simon will be holding a separate, short workshop on the reproducible research tools used at his institute. Join us to learn how to implement these transparent workflows in your own analysis. 

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Motherhood is associated with persistent penalties in both labour market outcomes and health. However, the role of family policies in mitigating these effects, particularly with respect to maternal mental health, remains unclear. This paper examines the impact of extending paternity leave on maternal mental health. Using administrative health records covering all publicly funded births in Catalonia (Spain) between 2006 and 2024, we implement a local difference-in-differences design around the April 1st, 2019 reform, which introduced partially mandatory paternity leave for fathers. The analysis focuses on first time mothers giving birth within a three-month window around the reform cutoff and compares them to a control cohort from 2016. Maternal mental health is measured using diagnoses and prescription records for stress-related, mood-related, and broader mental health conditions drawn from primary care and pharmacy data. We find an increase in stress-related diagnoses and in the use of antidepressants and anxiolytics from the second year after childbirth among mothers exposed to the reform. These effects are concentrated among older mothers (above the median age of 31) and among those who do not have a second child within four years after birth. We find suggestive evidence that these patterns may be related to increased healthcare use and to stress-related mechanisms, including delayed fertility, changes in labour market attachment, and relationship instability. Ongoing work will extend the analysis to additional mental health outcomes and to subsequent paternity leave reforms

This event is both online and in person. Join the Teams meeting

This event is both online and in person. Join the Teams meeting

This event is both online and in person. Join the Teams meeting