Examination and visualisation of the simplifying assumption for vine copulas in three dimensions

Vine copulas are a highly flexible class of dependence models, which are based on the decomposition of the density into bivariate building blocks. For applications one usually makes the simplifying assumption that copulas of conditional distributions are independent of the variables on which they are conditioned. However this assumption has been criticised for being too restrictive. We examine both simplified and non‐simplified vine copulas in three dimensions and investigate conceptual differences. We show and compare contour surfaces of three‐dimensional vine copula models, which prove to be much more informative than the contour lines of the bivariate marginals. Our investigation shows that non‐simplified vine copulas can exhibit arbitrarily irregular shapes, whereas simplified vine copulas appear to be smooth extrapolations of their bivariate margins to three dimensions. In addition to a variety of constructed examples, we also investigate a three‐dimensional subset of the well‐known uranium data set and visually detect the fact that a non‐simplified vine copula is necessary to capture its complex dependence structure.     

Engaging diverse experts in a global environmental assessment: participation in the first work programme of IPBES and opportunities for improvement

The need for interdisciplinary expert groups from different regions of the world to be involved in the fields of sustainability science and environmental change research is increasingly recognised. The Intergovernmental Platform on Biodiversity and Ecosystem Services (IBPES) was established in 2012 as a science-policy interface and has gone beyond previous initiatives in its articulation of a clear commitment to inter- and transdisciplinary approaches that mandate a diversity of genders, disciplines and regional backgrounds within its expert groups. The first IPBES work programme, carried out between 2014 and 2018, has been supported by 17 expert groups, comprising over 1000 experts, who have been selected from over 2000 government and stakeholder nominations through formal procedures. In this paper, we present and critique the framework through which IPBES identifies and selects experts to participate in its processes. In addition, we synthesise and carry out a quantitative analysis on the expert nomination and selection data relating to the first assessment activities of IPBES. Identifying that the balance of regions, genders, disciplines and knowledge systems represented within these expert groups is still disproportionally dominated by male natural scientists from the Global North, the paper makes recommendations of how to better engage knowledge holders from different disciplines and diverse knowledge systems in future iterations of the IPBES work programme.     

“We are not strippers”: How Belly Dancers Manage a (Soft) Stigmatized Serious Leisure Activity

Most stigma research examines people who engage in deviant activities or possess visible and permanent discredited attributes, which lead to “hard” or severe consequences. Existing leisure studies focus on the benefits of leisure pursuits. Less attention is paid to the potential costs associated with serious leisure, such as “soft” stigma. The snubs and slight embarrassments resulting from soft stigma may jeopardize the rewards people receive from participating in leisure, such as a sense of identity, self‐worth, and pride. Using interviews with seventy‐four female belly dancers, most of whom belly dance as a form of “serious leisure,” this article examines how dancers manage perceptions that they are erotic dancers. Results show that dancers use an interesting set of stigma management techniques and new forms of some existing management strategies to simultaneously protect themselves and enhance the reputation of the group. Implications for how people negotiate soft stigma associated with serious leisure are discussed.     

Die Umzugsentscheidung von Paaren als Verhandlungsproblem

Recently bargaining models became a popular theoretical concept within family research. Especially compared to household economic theory, bargaining models are less abstract and provide a tool for analysis of conflicting interests and their consequences in family relationships. However, although there are many different topics which can be tackled with this kind of theory, there is still a lack of direct empirical tests concerning this concept. The aim of this article is to provide such a test by using a special type of a quasi-experimental research design. With a so-called factorial design we vary systematically incentives for a household move in order to model different structural conditions of a relationship like earning possibilities or chances for a career of a partner. This allows us to observe varying power allocations within the relationship. The empirical results support the hypotheses derived from the bargaining model: the respondent anticipates a loss of his or her bargaining power as well as an increasing power of the partner. Consequently they answer such a change with a reduced tendency for a household move and a higher perceived potential for conflicts within the relationship. However, due to our limited knowledge about the validity of the quasi-experimental design these results need to be validated by future research.     

Cognitive Components of Risk Ratings

This study examined what lay people mean when they judge the "risk" of activities that involve the potential for accidental fatalities (e.g., hang gliding, living near a nuclear reactor). A sample of German and American students rated the "overall risk" of 14 such activities and provided 3 fatality estimates: the number of fatalities in an "average year," the individual yearly fatality probability (or odds), and the number of fatalities in a "disastrous accident." Subjects' fatality estimates were reasonably accurate and only moderately influenced by attitudes towards nuclear energy. Individual fatality probability correlated most highly with intuitive risk ratings. Disaster estimates correlated positively with risk ratings for those activities that had a low fatality probability and a relatively high disaster potential. Annual average fatality rates did not correlate with risk ratings at all. These findings were interpreted in terms of a two-dimensional cognitive structure. Subjective notions of risk were determined primarily by the personal chance of death; for some activities, "disaster potential" played a secondary role in shaping risk perception.     

Data-driven smooth tests of the proportional hazards assumption

A new test of the proportional hazards assumption in the Cox model is proposed. The idea is based on Neyman’s smooth tests. The Cox model with proportional hazards (i.e. time-constant covariate effects) is embedded in a model with a smoothly time-varying covariate effect that is expressed as a combination of some basis functions (e.g., Legendre polynomials, cosines). Then the smooth test is the score test for significance of these artificial covariates. Furthermore, we apply a modification of Schwarz’s selection rule to choosing the dimension of the smooth model (the number of the basis functions). The score test is then used in the selected model. In a simulation study, we compare the proposed tests with standard tests based on the score process.     

Diskussionslinien der Entrepreneurial Marketing-Forschung: Ergebnisse einer Zitationsanalyse

Entrepreneurial Marketing (EM) is a research field that grows dynamically and that seems to be heterogeneous. Heterogeneity of a research field exacerbates the orientation in and the advancement of the field. Therefore, this article strives to inventarize the EM-literature and thereby to identify key discussion lines of EM research.Based on a comprehensive literature analysis, we first outline the history of EM research, and identify core authors and core journal Based on a citation analysis of 199 EM papers with a total of 6,222 references and an ensuing expert evaluation, we identify four key discussion lines: (1) theoretical foundations, (2) entrepreneurship-marketing interface, (3) new venture- and SME-marketing, and (4) EM in the sense of innovative, proactive and risk-oriented marketing. These four discussion lines and the respective literature constitute a framework for the advancement of EM research.     

„Unkündbar und nun?“ Lebensziel oder Schicksalsschlag – Chancen für eine faire Trennungskultur in der öffentlichen Verwaltung

Job security is seen as a very high value by employees regarding their professional objectives. Especially for employees in public service that secure professional status is one of their main reasons for working in public servance. Therefore, any dismissal may have severe negative effects on health of the employees and also negative effects on the image of the employer. From their perspective, an outplacement program could be an expedient element within the employee-life-cycle (recruiting—retention—exit/outplacement). A fair culture of separation in the organizational context in public sector which is accompanied by an outplacement program can give new perspectives to the employees and strengthen the image of the employer. An interview study with clients of an outplacement consultation will be mentioned. The participants were asked about their expectations and experiences with the consultation. Basically, the results clearly show that the consultant has a tremendous importance and is thus one of the most important success factors. If he or she meets the needs of the client, he or she works up the separation and promotes the confidence of his clients, nothing stands in the way of a successful consultation.     

The transmission of socioeconomic status and prestige in Great Britain and the United States

We analyze male occupational attainment using separate models in which occupational level is measured by indigenous socioeconomic index (SEI) scales, indigenous prestige scales, and a common prestige scale. Other than some consistent societal differences, the SEI scales produce highly similar results in both societies. In sharp contrast, both indigenous and common prestige scales indicate a stronger relative effect of origin (compared with education) on occupation in Great Britain. The dimensions of prestige and socioeconomic status thus seem to tap different aspects of the social mobility process, and the societies differ in the transmission of prestige but not socioeconomic status.