We consider endogenous binary treatment with multiple binary instruments. We propose a novel limited monotonicity (LiM) assumption that is generally weaker than alternative monotonicity assumptions in the literature. We define and identify (under LiM) the combined compliers local average treatment effect (CC-LATE), which is arguably a more policy-relevant parameter than the weighted average of LATEs identified by two-stage least squares (TSLS), and is valid under more general conditions. Estimating the CC-LATE is trivial, equivalent to running TSLS with one constructed instrument on a subsample. We use our CC-LATE to empirically assess how knowledge of HIV status influences protective behaviors. If time permits I will also present my recent work on the Synthetic Control Method.

Startup companies solve many of today’s most challenging problems, such as the decarbonisation of the economy or the development of novel life-saving vaccines. Startups are a vital source of innovation, yet the most innovative are also the least likely to survive. In this research project, we aim to disentangle the determinants of success in entrepreneurship at three levels, ranging from the personalities in the founder team (mico-level), the role of startup incubator programmes (meso-level), and the larger innovation ecosystem (macro-level) in driving the success of startup companies. The project utilises data science, computational, and complex systems research methods. In the talk, we focus mainly on our foundational research study, ‘The impact of founder personalities on startup success’, published in Nature Scientific Reports (McCarthy et al., 2023, more than 86,000 downloads to date) to show that founder personality traits are a significant feature of a firm’s ultimate success. We draw upon detailed data about the success of a large-scale global sample of startups. We find that the Big Five personality traits of startup founders across 30 dimensions significantly differ from that of the population at large. Key personality facets that distinguish successful entrepreneurs include a preference for variety, novelty and starting new things (openness to adventure), like being the centre of attention (lower levels of modesty) and being exuberant (higher activity levels). We do not find one ’Founder-type’ personality; instead, six different personality types appear. Our results also demonstrate the benefits of larger, personality-diverse teams in startups, which show an increased likelihood of success. The findings emphasise the role of the diversity of personality types as a novel dimension of team diversity that influences performance and success.

Healthcare systems worldwide are complex service networks with many dependencies and interrelations. Within these networks, hospitals play a central role and serve as one of the key providers of healthcare services. Efficient and high-quality service requires the necessary resources such as personnel and beds to be dimensioned correctly and to be available in the right place at the right time. Typically, resource-related planning problems are treated separately for each resource without integrated planning across several resources, leading to sub-optimal solutions. In practice, these problems are often dealt with by clinical staff who are not trained for this kind of complex decisions, and it also reduces their available time for patient treatment and care. Optimisation approaches, ideally paired with simulation models, can support decision making in healthcare practice, reduce the workload for clinical staff and decision makers and improve different objectives including efficiency, staff or patient satisfaction, quality of care or costs. In a hospital, all departments are connected, and every logistical decision can impact others. Due to the complexity, it is not possible to build mathematical optimisation models that address all aspects simultaneously. In addition, some decisions must be made onsite and in real-time. Simulation models can help with online decision making as well as analysing the potential consequences when transferring solutions from mathematical models into practice. With the support of the Julius von Haast Fellowship by the Royal Society of New Zealand, we aim to design an integrated simulation framework to model a complete hospital allowing to investigate all interdependencies and improvement potentials and to analyse the benefit of integrated planning. In this talk, we want to give a motivation for integrated planning in healthcare and the hospital-wide simulation framework as well as a brief overview of the existing literature. In addition, first insights from a simulation study integrating emergency departments and (overflow) wards will be presented.

The gender gap in start-ups is an important source of inefficiency. We show that negative, gender-specific, spillovers resulting from fraudulent behaviour of women entrepreneurs can exacerbate this gap. Our study focuses on the fraud committed by one of the world's most promising biotech start-ups, Theranos, and its female founder Elizabeth Holmes. We find that the average investment volume in female-led start-ups drops by 18\% after the uncovering of the fraud. This represents a doubling of the gender gap in financing. Evidence further indicates that female entrepreneurs are turning to government grants in response to the increasingly adverse conditions in the private capital market. As the average value of grants is orders of magnitude smaller than the average investment raised in the private market, this implies that the spillovers generate substantial welfare losses. We further find that negative gender-specific effects extend beyond start-ups. The share prices of companies led by female CEOs drop following the exposure of the Theranos fraud.

The aging of the general physician workforce in developed countries is expected to lead to increased practice closures. Hence, concerns arise regarding the health effects of such closures, particularly for patients facing them during critical life stages such as pregnancy. However, no study exists to date on the health effects of general physi- cians’ (GP) practice closures during pregnancy. I assess the effects of such closures during pregnancy on birth outcomes in Denmark. I compare the birth outcomes of mothers experiencing practice closures within nine months post-conception to those facing closures nine months pre-conception. I find a small to medium-sized adverse effect of discontinuity in care on birth outcomes. The negative effect on birth weight is especially pronounced when the closure happens in the last trimester of pregnancy. Consistently, mothers affected by GP practice closures during pregnancy experience small disruptions in healthcare provision at the extensive and at the intensive margin.

In this study, we use the concept of functional affordances of information systems to develop a novel theoretical framework that links firms’ digitalization intensity to their ecological performance. Specifically, we propose that digitalization intensity reduces firms’ impact on the natural environment and enhances their capability for ecological innovations. To contextualize these relationships, we introduce corporate governance and service industry membership as essential contingencies for this link. Results of our panel regression analyses widely support our theorizing.