CCR or BCC: what if we are in the wrong model?

The CCR model by Charnes et al. (Eur J Oper Res 2:429–444, 1978) together with the BCC model by Banker et al. (Manag Sci 30:1078–1091, 1984) are the most popular approaches of measuring efficiency among a group of decision making units, DMUs, in data envelopment analysis, DEA. The right choice of a DEA model—CCR or BCC—often, if not always, is a difficult decision. To evaluate a DMU’s efficiency for both models might be helpful, but it does not always capture the essential issues at stake. In this paper we propose a comparative analysis of both concepts: How does activity scaling under constant BCC-efficiency influence CCR-efficiency. And inversely, how does BCC-efficiency behave when activity scaling under constant CCR-efficiency is applied. Such findings of mutual effects improve a DMU’s ability to reassess upsizing and downsizing of activities. Moreover, it allows for exact calculations of the resulting economic effects, and these effects give new insights beyond classical DEA. Finally, scale efficiency turns out to be the ideal concept to control these activity changes, rather than just CCR- or BCC-efficiency. We use a little numerical example to emphasize advantages of the new concept and sketch the new findings for a theater scenery.     

Discourses of service user involvement in meeting places in Norwegian community mental health care: a discourse analysis of staff accounts

In previous research, meeting places have been favourably addressed by service users, but they have also been contested as exclusionary. In this participatory explorative study, we sought to perform a contextual analysis of meeting places in Norway based on a discourse analysis of three focus group discussions with 15 staff members. We asked the following question: how do meeting-place employees discuss their concrete and abstract encounters with service users and their experiences? We focused on service user involvement, which was largely analysed as neoliberal consultation and responsibilisation. Service users were positioned as resisting responsibility trickling down and defending staffed meeting places. Social democratic discourse was identified in the gaps of neoliberal discourse, which is noteworthy given that Norway is a social democracy. This relates to global concerns about displacements of democracy. We suggest that meeting places appear to hold the potential for staff and service users to collaborate more democratically.     

Die Anderen als sozialer Kontext. Zur Bedeutung strategischer Interaktion

An action is defined as “strategic” when the consequences of ego’s action depend on the action of alter. Situations of strategic interaction are numerous in daily life, business, and politics. Pioneers like Erving Goffman or Raymond Boudon recognized the importance of strategic interaction in sociological analysis long ago. Other peoples’ opportunities of actions form ego’s strategic context. The dynamics of the impact of the strategic context on ego’s action can be modeled and analyzed by means of game theory. We will discuss three examples of strategic interaction models: “Diffusion of responsibility”, Boudon’s “logic of relative frustration”, and the problem of social exchange and trust. We demonstrate the effects of the strategic context on the opportunities and beliefs of actors. In contrast to non-strategic rational choice theory, beliefs and opportunities are not assumed as exogenous. The analysis of the strategic context contributes to a better understanding of the micro-level effects and the macro-level implications. However, the strict rationality requirements of game models are often violated. In these situations, evolutionary models based on principles of learning and adaptions are more adequate than models based on assumptions of strict rationality.     

Variable selection in discrete survival models including heterogeneity

Several variable selection procedures are available for continuous time-to-event data. However, if time is measured in a discrete way and therefore many ties occur models for continuous time are inadequate. We propose penalized likelihood methods that perform efficient variable selection in discrete survival modeling with explicit modeling of the heterogeneity in the population. The method is based on a combination of ridge and lasso type penalties that are tailored to the case of discrete survival. The performance is studied in simulation studies and an application to the birth of the first child.     

Career Engagement: Investigating Intraindividual Predictors of Weekly Fluctuations in Proactive Career Behaviors

This study applied a microlevel perspective on how within‐individual differences in motivational and social‐cognitive factors affected the weekly fluctuations of engagement in proactive career behaviors among a group of 67 German university students. Career self‐efficacy beliefs, perceived career barriers, experienced social career support, positive and negative emotions, and career engagement were assessed weekly for 13 consecutive weeks. Hierarchical linear regression analyses showed that above average levels of career engagement within individuals were predicted by higher than average perceived social support and positive emotions during a given week. Conversely, within‐individual differences in self‐efficacy, barriers, and negative emotions had no effect. The results suggest that career interventions should provide boosts in social support and positive emotions.     

(Un)Gleichheit durch soziale Schlie?ung

The concept of social closure is frequently used in recent debates about wage inequality. The following article shows that social closure generates not only inequality but equality, as well. Economic, segmentational and closure theoretical arguments shed light on the different relations of an employee to his employer in different labour market structures. Properties of the employee like vocational training, seniority or gender lose their impact on wages the more closed a labour market is. These hypotheses are tested with the 2006 BIBB/BAuA-Employment-Survey. Results support a deep effect of social closure in the German labour market.     

Sensitivity Analysis Using Risk Measures

In a quantitative model with uncertain inputs, the uncertainty of the output can be summarized by a risk measure. We propose a sensitivity analysis method based on derivatives of the output risk measure, in the direction of model inputs. This produces a global sensitivity measure, explicitly linking sensitivity and uncertainty analyses. We focus on the case of distortion risk measures, defined as weighted averages of output percentiles, and prove a representation of the sensitivity measure that can be evaluated on a Monte Carlo sample, as a weighted average of gradients over the input space. When the analytical model is unknown or hard to work with, nonparametric techniques are used for gradient estimation. This process is demonstrated through the example of a nonlinear insurance loss model. Furthermore, the proposed framework is extended in order to measure sensitivity to constant model parameters, uncertain statistical parameters, and random factors driving dependence between model inputs.     

Decision model for product rollover in manufacturing operations

The purpose of this study is to investigate critical decisions when planning for product rollover at a manufacturing company, and how to organise these decisions. A literature review and a case study are used to develop a decision model. The findings indicate that product rollover can be organised in a five-phase decision model. The research quality is strengthened by a structured literature review, but it can be argued that more empirical research is needed for validation. For researchers, this paper contributes with the identification of critical decisions and a model for product rollover. For practitioners, the study highlights the need to acknowledge the importance of product rollover and its role as a competitive weapon. In earlier studies, product rollover has mainly been investigated from a market perspective, so that this study contributes by investigating the issue from a manufacturing perspective.