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.     

Trend effects on perceived avalanche hazard

Hazard-level forecasts constitute an important risk mitigation tool to reduce loss of economic values and human life. Avalanche forecasts represent an example of this. As for many other domains, avalanche risk is communicated using a color-coded, categorical risk scale aimed at informing the public about past, current, and future risk. We report the results from three experiments in which we tested if an irrelevant past trend in forecasted avalanche danger affects perceptions of current and future avalanche risk. Our sample consisted of individuals from three different populations targeted by national avalanche warning services. All three experiments showed that the perception of avalanche risk is influenced by the trend, but that the effect is opposite for perceptions of current and expectations of future avalanche risk. While future avalanche risk is extrapolated in the same direction as the change from the previous day, we found that perceived current risk appears to be based on an average of past and current risk. These effects diminish when we provide participants with a scale indicating the exact level of avalanche danger. For most of our measurement instruments, however, the effects remain significant. These results imply that targeted populations may consider historic information more than was intended by the sender. As such, our results have implications for both avalanche warning services and risk communication in general.     

Die Rolle des Luftverkehrsrechts und der Haftung bei Flugzeugkatastrophen: Eine Finanzmarktanalyse

Zusammenfassung  Rechtsansprüche gegen Fluggesellschaften und Flugzeughersteller in Folge einer Flugzeugkatastrophe richten sich nach einer Flut rechtlicher Bestimmungen, die aus internationalen Abkommen, Vereinbarungen zwischen Fluglinien sowie aus Bundes- und Landesrecht resultieren. Die jeweilige Rechtsgrundlage in einem spezifischen Fall h?ngt von verschiedenen Umst?nden ab, die mit einem Unfall verbunden sind. Es überrascht daher nicht, dass zugesprochene Schadensersatz- und Schmerzensgeldzahlungen an die Angeh?rigen der Opfer von Fall zu Fall erheblich divergieren. In unserer Studie mit U.S.-amerikanischen Daten untersuchen wir, inwieweit der kurz- und langfristige Erfolg von Fluggesellschaften und Flugzeugherstellern durch Flugzeugkatastrophen beeinflusst wird und wir eruieren diejenigen Determinanten, die Performanceunterschiede erkl?ren k?nnen. Verwandte Untersuchungen haben sich weitgehend auf Effekte für Markennamen oder steigende Versicherungspr?mien als Ursachen für Aktienkursverluste konzentriert. Unsere Ergebnisse zeigen darüber hinaus, dass das regulatorische Umfeld einer spezifischen Unglückssituation erheblichen Einfluss darauf hat, wie Finanzm?rkte reagieren. Die Reaktionen der Marktteilnehmer weisen darauf hin, dass die unterschiedlichen Berechnungsgrundlagen für die Opferentsch?digung recht klar erkannt werden.

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The role of aviation laws and legal liability in airplane accidents: A financial market perspective

Summary  Legal liability claims against airlines and airplane manufacturers following an aviation disaster are determined through a myriad of international treaties, intercarrier agreements, and federal and state laws. Which law applies in a specific situation depends on various circumstances surrounding the accident. As a result, pecuniary and non-pecuniary damage awards for the families of the accident victims may vary substantially from case to case. Using U.S. data, our study examines how aviation disasters affect the short and long-term performance of airlines and airplane manufacturers and explores the factors that drive the performance differences. While prior research has largely focused on brand name effects and rising insurance premiums as possible determinants of stock price losses, our results suggest that the regulatory environment that applies to a given aviation accident has a significant impact on how the market reacts to its announcement. Inequities in the valuation of a human life are clearly reflected in stock price reactions. While recent regime changes have helped eliminate some of these imbalances further reform may be necessary.

     

The surprising effectiveness of earliest operation due-date sequencing

In make-to order production, schedule reliability is very important but still not sufficiently accomplished in industrial practice by the vast majority of companies. It has been known for long that processing the orders at a workstation in the order of their operation due-dates can compensate for lateness in the arrival at the workstation within certain boundaries. The paper analyses the effectiveness of earliest operation due date (EODD) sequencing by comparing it to an optimistic theoretical boundary. The surprising result is that EODD can nearly fully exploit the theoretical potential. It should therefore be used in practice whenever schedule reliability is important, with only few exceptions. Its effectiveness though is increasing with the workstation’s WIP level and thus is in conflict with the objective to reduce WIP levels and throughput times. A simple forecasting model allows to assess the extent to which lateness can be compensated by EODD sequencing and which schedule compliance can be achieved.     

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.     

THE REPLACEMENT PROBLEM IN FRICTIONAL ECONOMIES: A NEAR‐EQUIVALENCE RESULT

We examine how technological change affects wage inequality and unemployment in a calibrated model of matching frictions in the labor market. We distinguish between two polar cases studied in the literature: a “creative destruction” economy, where new machines enter chiefly through new matches and an “upgrading” economy, where machines in existing matches are replaced by new machines. Our main results are: (i) these two economies produce very similar quantitative outcomes, and (ii) the total amount of wage inequality generated by frictions is very small. We explain these findings in light of the fact that, in the model calibrated to the US economy, both unemployment and vacancy durations are very short, i.e., the matching frictions are quantitatively minor. Hence, the equilibrium allocations of the model are remarkably close to those of a frictionless version of our economy where firms are indifferent between upgrading and creative destruction, and where every worker is paid the same market‐clearing wage. These results are robust to the inclusion of machine‐specific or match‐specific heterogeneity into the benchmark model. (JEL: J41, J64, O33)     

Entscheidungsverhalten von Kunden in Mass Customization-Systemen

Sequential choice processes are ubiquitous in consumer decision making. In each attribute decision, consumers are often faced with different numbers of options which they must trade off in order to make the best possible choice. Thereby, complicated high variety choices at the beginning of a choice process produce a larger trade-off conflict and, thus, initially a greater mental depletion than more simple low variety choices. We examine the strength of mental depletion in sequential choices on individuals’ perceived attractiveness of the firm’s recommended default option at a target choice. We show that consumers who are confronted with difficult high variety choices early in the decision sequence followed by low variety choices initially deplete more than consumers who encounter exactly the same attribute decisions in reverse. As a result, depleted consumers are more likely to fall prey to the recommended default or some perceptually focal options close to the default anchor at target choice succeeding a sequence of decisions.     

Modified Wald statistics for generalized linear models

Summary: Wald statistics in generalized linear models are asymptotically ² distributed. The asymptotic chi–squared law of the corresponding quadratic form shows disadvantages with respect to the approximation of the finite–sample distribution. It is shown by means of a comprehensive simulation study that improvements can be achieved by applying simple finite–sample size approximations to the distribution of the quadratic form in generalized linear models. These approximations are based on a ² distribution with an estimated degree of freedom that generalizes an approach by Patnaik and Pearson. Simulation studies confirm that nominal level is maintained with higher accuracy compared to the Wald statistics.     

Robust variable selection with application to quality of life research

A large database containing socioeconomic data from 60 communities in Austria and Germany has been built, stemming from 18,000 citizens’ responses to a survey, together with data from official statistical institutes about these communities. This paper describes a procedure for extracting a small set of explanatory variables to explain response variables such as the cognition of quality of life. For better interpretability, the set of explanatory variables needs to be very small and the dependencies among the selected variables need to be low. Due to possible inhomogeneities within the data set, it is further required that the solution is robust to outliers and deviating points. In order to achieve these goals, a robust model selection method, combined with a strategy to reduce the number of selected predictor variables to a necessary minimum, is developed. In addition, this context-sensitive method is applied to obtain responsible factors describing quality of life in communities.