Publikationen

This paper exploits the idea of combining pretesting and bagging to choose between competing portfolio strategies. We propose an estimator for the portfolio weight vector, which optimally trades off Type I against Type II errors when choosing the best investment strategy. Furthermore, we accommodate the idea of bagging in the portfolio testing problem, which helps to avoid sharp thresholding and reduces turnover costs substantially. Our Bagged Pretested Portfolio Selection (BPPS) approach borrows from both the shrinkage and the forecast combination literature. The portfolio weights of our strategy are weighted averages of the portfolio weights from a set of stand-alone strategies. More specifically, the weights are generated from pseudo-out-of-sample portfolio pretesting, such that they reflect the probability that a given strategy will be overall best performing. The resulting strategy allows for a flexible and smooth switch between the underlying strategies and outperforms the corresponding stand-alone strategies. Besides yielding high point estimates of the portfolio performance measures, the BPPS approach performs exceptionally well in terms of precision and is robust against outliers resulting from the choice of the asset space.

Multimodal deep learning models have been applied for disease prediction tasks, but difficulties exist in training due to the conflict between sub-models and fusion modules. To alleviate this issue, we propose a framework for decoupling feature alignment and fusion (DeAF), which separates the multimodal model training into two stages. In the first stage, unsupervised representation learning is conducted, and the modality adaptation (MA) module is used to align the features from various modalities. In the second stage, the self-attention fusion (SAF) module combines the medical image features and clinical data using supervised learning. Moreover, we apply the DeAF framework to predict the postoperative efficacy of CRS for colorectal cancer and whether the MCI patients change to Alzheimer’s disease. The DeAF framework achieves a significant improvement in comparison to the previous methods. Furthermore, extensive ablation experiments are conducted to demonstrate the rationality and effectiveness of our framework. In conclusion, our framework enhances the interaction between the local medical image features and clinical data, and derive more discriminative multimodal features for disease prediction. The framework implementation is available at github.com/cchencan/DeAF.

We investigate how the intensity of Ramadan affects educational outcomes by exploiting spatio-temporal variation in annual fasting hours. Longer fasting hours are related to increases in student performance in a panel of TIMSS test scores (1995–2019) across Muslim countries but not other countries. Results are confirmed in a panel of PISA test scores (2003–2018) allowing within country-wave comparisons of Muslim to non-Muslim students across Europe. We provide evidence that a demanding Ramadan affects PISA test scores of Muslim students only in cohorts with a large share of co-religionists. This finding is consistent with the hypothesis that shared experiences during more intensive Ramadans facilitate the formation of social capital and a social identity conducive to learning outcomes.

We discuss combining sign restrictions with information in external instruments (proxy variables) to identify structural vector autoregressive (SVAR) models. In one setting, we assume the availability of valid external instruments. Sign restrictions may then be used to identify further orthogonal shocks, or as an additional piece of information to pin down the shocks identified by the external instruments more precisely. In a second setting, we assume that proxy variables are only “plausibly exogenous” and suggest various types of inequality restrictions to bound the relation between structural shocks and the external variable. This can be combined with conventional sign restrictions to further narrow down the set of admissible models. Within a proxy-augmented SVAR, we conduct Bayesian inference and discuss computation of Bayes factors. They can be useful to test either the sign- or IV restrictions as overidentifying. We illustrate the usefulness of our methodology in estimating the effects of oil supply and monetary policy shocks.

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dc.contributor.author: Neuenschwander, Markus P.; Ramseier, Lukas

There is agreement among health economists that on the whole medical innovation causes health care expenditures (HCE) to rise. This paper analyzes for which diagnoses HCE per patient have grown significantly faster than average HCE. We distinguish decedents (patients in their last 4 years of life) from survivors and use a unique dataset comprising detailed HCE of all members of a regional health insurance fund in Upper Austria for the period 2005-2018. Our results indicate that among decedents in particular, the expenditures for treatment of neoplasms have exceeded the general trend in HCE. This confirms that medical innovation for this group of diseases has been particularly strong over the last 15 years. For survivors, we find a noticeable growth in cases and cost per case for pregnancies and childbirth, and also for treatment of mental and behavioral disorders. We discuss whether these findings contradict the widespread interpretation of cost-increasing innovations as "medical progress" and offer some policy recommendations.

Against the background of digital transformation processes that are currently changing the world of work, this paper examines general digital competences of beginning trainees in commercial vocational education and training (VET) programs. We are particularly interested in factors influencing digital competence profiles. From survey data including N = 480 trainees in one federal state in Germany, we were able to identify three different competence profiles (based on the trainees’ self-assessment of their general digital competence). Initial descriptive analysis reveals differences between competence profiles of different training professions (industrial clerks and retail salespersons reach higher competence levels than salespersons). However, regression results indicate that these differences can be explained by differences in school leaving certificates. Contrary to prior empirical evidence, we find no significant effect of trainees’ gender. Finally, the frequency of certain private digital activities (e.g. using office programs, conducting internet searches) affects digital competence profiles. Implications for both VET programs and further research are discussed.

The choice of a study program is based on complex individual decision-making processes. Thereby, economics is one of the most popular fields of study worldwide. Considering previous studies, the role of the teacher is often neglected. However, it can be assumed that teachers’ professional knowledge plays a significant role in a student’s choice of a study program. Thus, the present study investigated the influence of the professional knowledge that students perceive in their economics teacher on their aspirations and choice of an economics study program. The longitudinal data of 1387 Swiss high school students were analyzed. Economic competencies were measured multidimensionally and included knowledge, motivation, interest, value-oriented dispositions, and attitude. There were small to moderate correlations between the professional knowledge that students perceived in their economics teacher and their economic competencies. With regard to the intention and choice of economics, the results show small to moderate effects of the pedagogic content knowledge and the general pedagogic knowledge that students perceive in their teacher. These findings contribute to the discussion on the role of the economics teacher. It is therefore recommended that the teaching professionalism of economics teachers, which has been criticized in different countries, be promoted more strongly and more systematically.

People often have to judge the social motives of others, for example, to distinguish truly prosocial people from those merely trying to appear prosocial. Gaze can reveal the motives underlying social decisions, as decision-makers dedicate more attention to motive-relevant information. We extend the use of eye-tracking and apply it as a communication device by providing (real-time) eye-tracking information of one participant to another. We find that untrained observers can judge the prosociality of decision-makers from their eye-tracked gaze alone, but only if there are no strategic incentives to be chosen for a future interaction. When there are such strategic incentives, the cues of prosociality are invalidated, as both individualistic and prosocial decision-makers put effort into appearing more prosocial. Overall, we find that gaze carries information about a person's prosociality, but also that gaze is malleable and affected by strategic considerations.

Die Bundesregierung will das System der Grundsicherung für Arbeitsfähige radikal reformieren. Neben der Abschaffung des Vermittlungsvorrangs und der Stärkung der Qualifizierung will sie vor allem die Zuverdienstmöglichkeiten für Hilfeempfänger:innen verbessern. Fachleute zerbrechen sich schon lange den Kopf, wie die prohibitiv hohen Transferentzugsraten, also die Anrechnung von Markteinkommen auf den Transfer, auf ein erträgliches Maß gesenkt werden können, ohne dass das System zu teuer wird. Eine Lösung könnte in einer Variante des „Workfare“-Modells liegen, die aus einer Absenkung des Sockeltransfers und einer Arbeitsplatzgarantie des Staates besteht, sodass jeder Arbeitsfähige zur Deckung seines Grundbedarfs durch Arbeit beiträgt.

We present a simple model, illustrating how democracy may improve the quality of the economic institutions. The model further suggests that institutional quality varies more across autocracies than across democracy and that the positive effect of democracies on economic institutional quality increases in people’s human capital. Using a panel data set that covers 150 countries and the period from 1920 to 2019, and different measures of economic institutional quality, we show results from fixed effect and instrumental variable regressions that are in line with the predictions of our model.

In Germany, young migrants and refugees whose German language skills are not sufficient for attending regular classes at school are assigned to so-called “preparation classes”. As the name implies, the main objective of these classes is to teach German language skills and thereby prepare students for regular classes or vocational education and training. Teachers in these classes face special challenges: They have to teach a group of students that is highly heterogeneous in several key respects, they have to deal with a dearth of institutional support and guidance, and they have a lot of responsibility regarding their students' integration in Germany. Therefore, this paper asks what target group-specific professional knowledge teachers possess and to what extent this knowledge reduces the teachers' burdens and raises their perception of gains and contributions to their students' success. Our mixed-method survey of 48 teachers of refugees in prevocational preparation classes in Germany shows that the majority of teachers acquired useful knowledge for teaching refugees, e.g., dealing with trauma and post-traumatic stress disorder, building German proficiency, or language-sensitive teaching, by attending professional training. In sum, most of the teachers saw immigration to Germany as both a problem and an opportunity. The main burdens they identify are bad working conditions, a lack of support and appreciation and a high demand for high flexibility. Despite generally low stress levels and high resilience, the teachers were extremely stressed by the heterogeneity in their students' performance, especially those teachers who had completed professional training. However, teachers appreciated the students' willingness to learn and gratitude, and perceived cultural diversity in the classroom as a gain for themselves and their teaching. The teachers felt they had mostly contributed to their students' acquisition of the German language as well as their educational progress in general and their personal development. Students' chances of success are expected to be especially high in the German language acquisition and the management of everyday life in Germany. The assessments of teachers with and without target group-specific professional knowledge differ only slightly and rarely significantly.

Governments in developing countries struggle to reach intended beneficiaries when targeting social transfers towards vulnerable populations. Rates of eligible individuals not receiving social transfers and ineligible individuals receiving them tend to be high, constraining the effectiveness of such anti-poverty programs. While interventions to incentivize or monitor local agents in charge of selecting beneficiaries are typically expensive, an important complementary and cost-effective approach could be to reform eligibility criteria to facilitate the selection of beneficiaries. Whether reforms should focus on reducing the number of rules, or selecting criteria which are easy to verify, or do both remains an unanswered question. We address this knowledge gap based on India’s social pension scheme for elderly poor. We find that making eligibility criteria easier to verify has the potential to achieve a substantial improvement in the targeting performance through a reduction in the exclusion error. Those who meet the relevant criteria have a much higher chance of actually becoming beneficiaries. Since eligibility criteria can be changed at low cost, this suggests a viable route for reform in many developing countries. However, a major caveat remains that criteria must sufficiently well reflect actual poverty if the more accurate selection of beneficiaries according to formal criteria shall also translate into actual poverty reduction.

Angesichts der digitalen Transformation schulischer Kontexte ergeben sich neue Anforderungen an die berufliche Handlungskompetenz von Lehrkräften. Dies führt zu einem erhöhten Handlungsbedarf im Bereich der Lehrkräftefortbildung. Diese befindet sich als eine spezifische Form beruflicher Fortbildung an der Schnittstelle zwischen Lehrkräftebildung und Erwachsenen- und Weiterbildung, so dass eine Betrachtung dieser Lernkontexte aus dieser Perspektive subdisziplinübergreifende Impulse für die Umsetzung und Gestaltung von Lehrkräftefortbildung geben kann. Im Beitrag werden daher aktuelle Herausforderungen der Lehrkräftefortbildung vor dem Hintergrund der digitalen Transformation anhand des Mehrebenensystems der Erwachsenen- und Weiterbildung aufgezeigt und mit Blick auf die Erkenntnisse und Konzepte der Erwachsenen- und Weiterbildung diskutiert.

Schlenker’s model of responsibility was used in this study to investigate to what extent leadership trainers consider themselves accountable for the transfer of training. We conducted 15 semi-structured interviews and evaluated the answers using qualitative content analysis. With respect to the responsibility links of Schlenker’s model, the trainers described two out of three links as being rather strong. The interview data suggest that transfer-enhancing strategies were mostly clear to the trainers. They also reported feeling personally obliged to support trainees in their transfer efforts. Regarding the third link, the trainers perceived limited control over several transfer determinants. They explained that they could facilitate transfer but not produce it. The trainers identified the trainees, their supervisors, and the organisations as other responsible parties. The concept of trainers as transfer managers was scarcely reported among the data. Our findings suggest that client organisations could strengthen accountability by setting adequate and feasible training objectives and by monitoring their achievement. We discuss the theoretical and practical implications with regard to the promotion of transfer.