On the application of new tests for structural changes on global minimum-variance portfolios

We investigate if portfolios can be improved if the classical Markowitz mean–variance portfolio theory is combined with recently proposed change point tests for dependence measures. Taking into account that the dependence structure of financial assets typically cannot be assumed to be constant over longer periods of time, we estimate the covariance matrix of the assets, which is used to construct global minimum-variance portfolios, by respecting potential change points. It is seen that a recently proposed test for changes in the whole covariance matrix is indeed partially useful whereas pairwise tests for variances and correlations are not suitable for these applications without further adjustments.     

Hierarchie und Entlohnung

In this paper, we suggest a wage scheme that accounts for the hierarchical structure of an enterprise. We employ concepts of cooperative game theory and modify the van den Brink (2008) approach. Besides results on how the hierarchy affects wage differentials between levels of the hierarchy, we deal with the allocation of employees to the different levels.     

Attraktivität, Reziprozität und Lehrveranstaltungsevaluation

In this article we investigate the relationship between academic teachers’ attractiveness and their students’ evaluations of teaching. Furthermore it is examined, whether teachers’ grading influences students’ evaluations of teaching. Using data from an experimental design, hypotheses about attractiveness effects, frog-pond-effects, moderating gender effects and influences of grading are empirically tested. Controlling for confounding factors we find a very weak attractiveness effect, which can partly, but not only be ascribed to beauty’s productivity enhancing influence. Thereby, independently from the raters’ sex, female teachers profit from their looks. In contrast to that attractive male teachers are even sanctioned more strongly by their students for difficult tests than unattractive teachers. The frog-pond-hypothesis cannot empirically be supported: the attractiveness of teachers’ colleagues has no influence on the attractiveness effect. However, reciprocal evaluation behavior can consistently be found in the theoretical expected manner. It is substantially more relevant for students’ evaluations of teaching than attractiveness effects are. Alternative explanations for this grading effect can be excluded.     

Compliance check of gambler and youth protection in German amusement arcades: a pilot study

German gambling operators are required to identify problem gamblers at an early stage and exclude them from gambling on their premises. The main aim of this pilot study was to investigate the compliance of staff in Bremen’s amusement arcades. While visiting 29 of 111 amusement arcades, covert gamblers simulated signs of problematic gambling behaviour, arranged self-exclusions, monitored observance of the exclusion list and made fieldnotes about the staff’s reactions. The application of age checks was also tested. The findings showed that only in six cases (5%) did the staff adequately respond to evident signs of problematic gambling behaviour. Although 18 of 29 cases (62%) eventually resulted in self-exclusions or ban-like agreements, in some instances it was necessary to overcome major obstacles that emanated from the staff’s behaviour. During 15 subsequent follow-up visits, 13 banned mystery gamblers (87%) had no problems gambling on amusement-with-prizes (AWP) machines. Finally, just 26% of the 20- to 25-year-old mystery gamblers had their ID checked. The results indicate the necessity of regular external evaluations regarding the implementation of gambling harm-minimization measures in order to identify any shortcomings. In addition, the level of staff compliance may be increased by amending current legislation (e.g. by introducing a nationwide self-exclusion programme).     

Migration and Pacific Mortality: Estimating Migration Effects on Pacific Mortality Rates Using Bayesian Models

Pacific people living in New Zealand have higher mortality rates than New Zealand residents of European/Other ethnicity. The aim of this paper is to see whether Pacific mortality rates vary by natality and duration of residence. We used linked census-mortality information for 25- to 74-year-olds in the 2001 census followed for up to three years. Hierarchical Bayesian modeling provided a means of handling sparse data. Posterior mortality rates were directly age-standardized. We found little evidence of mortality differences between the overseas-born and the New Zealand–born for all-cause, cancer, and cardiovascular disease (CVD) mortality. However, we found evidence for lower all-cause (and possibly cancer and CVD) mortality rates for Pacific migrants resident in New Zealand for less than 25 years relative to those resident for more than 25 years. This result may arise from a combination of processes operating over time, including health selection effects from variations in New Zealand’s immigration policy, the location of Pacific migrants within the social, political, and cultural environment of the host community, and health impacts of the host culture. We could not determine the relative importance of these processes, but identifying the (modifiable) drivers of the inferred long-term decline in health of the overseas-born Pacific population relative to more-recent Pacific migrants is important to Pacific communities and from a national health and policy perspective.     

On the independence of history: experience spill-overs between experiments

A central understanding in experimental economics is that subjects’ decisions in the lab are independent of history. We test whether this assumption of between-experiment independence is indeed justified. We analyze experiments with an allocation decision (like a dictator or ultimatum game) and find that participation in previous experiments tends to increase the amount subjects allocate to themselves. Hence, independence between experiments cannot be presumed if subjects participate repeatedly. The finding has implications for the interpretation of previous allocation decision results and deserves attention when running future experiments.     

An Exploratory Study of Procurement Strategies for Multi‐Item RFQs in B2B Markets: Antecedents and Impact on Performance

This research explores procurement strategies for multi‐item requests for quotation (RFQs) in business‐to‐business (B2B) markets using responses from 825 purchasing professionals. The study first establishes procurement strategies that differ based on their level of strategic emphasis, i.e., the importance that is placed on the pursuit of four strategic objectives. Underlying objectives, which are obtained via factor analysis, include the focus on price, security of supply, internal procurement efficiencies, and bundle building. Next, cluster analysis is used to derive prototypical strategic approaches. The three cluster groups that emerge possess the same relative ranking of the four objectives, but differ based on the intensity with which these objectives are pursued. The clusters are labelled as the three strategic groups of strategists, opportunists, and responders. The research then explores, using an industrial buyer behavior lens, the impact of environmental antecedents in determining a particular strategy. Environmental variables include purchase importance, market uncertainty, supply base availability, buyer bargaining power, item experience, and supply base experience. Finally, the study tests the impact of procurement strategy on the buyer's perceived performance, suggesting that strategists, placing more emphasis on the pursuit of strategic sourcing objectives, achieve better performance than opportunists and responders.     

Public perceptions of hurricane modification

If hurricane modification were to become a feasible strategy for potentially reducing hurricane damages, it would likely generate public discourse about whether to support its implementation. To facilitate an informed and constructive discourse, policymakers need to understand how people perceive hurricane modification. Here, we examine Florida residents' perceptions of hurricane modification techniques that aim to alter path and wind speed. Following the mental models approach, we conducted a survey study about public perceptions of hurricane modification that was guided by formative interviews on the topic. We report a set of four primary findings. First, hurricane modification was perceived as a relatively ineffective strategy for damage reduction, compared to other strategies for damage reduction. Second, hurricane modification was expected to lead to changes in projected hurricane path, but not necessarily to the successful reduction of projected hurricane strength. Third, more anger was evoked when a hurricane was described as having changed from the initially forecasted path or strength after an attempted modification. Fourth, unlike what we expected, participants who more strongly agreed with statements that recognized the uncertainty inherent in forecasts reported more rather than less anger at scientists across hurricane modification scenarios. If the efficacy of intensity-reduction techniques can be increased, people may be willing to support hurricane modification. However, such an effort would need to be combined with open and honest communications to members of the general public.