920,443 research outputs found
Inference Using Non-Random Samples? Stop Right There!
No full textAbstract Statistical inference allows researchers to learn things about a population using only a sample of data from that population. But if it isn't a random sample, inference becomes tricky or outright impossible, as Norbert Hirschauer, Sven Grüner, Oliver Mußhoff, Claudia Becker and Antje Jantsch explai
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Investment planning under uncertainty and flexibility: the case of a purchasable sales contract
No full textInvestment decisions are not only characterised by irreversibility and uncertainty but also by flexibility with regard to the timing of the investment. This paper describes how stochastic simulation can be successfully integrated into a backward recursive programming approach in the context of flexible investment planning. We apply this hybrid approach to a marketing question from primary production which can be viewed as an investment problem: should grain farmers purchase sales contracts which guarantee fixed product prices over the next 10 years? The model results support the conclusion from dynamic investment theory that it is essential to take simultaneously account of uncertainty and flexibility
Non-metric data: a note on a neglected problem in DEA studies
No full textData envelopment analysis (DEA) is widely used to compare the empirical performance of public institutions such as law enforcement agencies, judicial authorities or national health care systems. Many DEA analysts, however, ignore the fact that DEA efficiency values are non-metric. They consequently do not hesitate to compute (arithmetic) means. They do not hesitate either to treat DEA values as metric data in econometric analyses. Instead of providing useful insights into the performance of public bodies, the confusion of non-metric data with metric data constitutes a lack of internal validity that may cause serious fallacies. Against this background, we believe that a clear warning against an uncritical processing and interpretation of DEA values is pertinent and should be routinely considered by efficiency analysts as well as referees of efficiency papers
Smarte Regulierung in der Ernährungswirtschaft durch Name-and-Shame
No full textEine Reihe von Lebensmittelskandalen der jüngeren Vergangenheit hat gezeigt, dass fehlgeleitete ökonomische Anreize eine bedeutsame Risikoquelle sind. Der Normappell des Gesetzes reicht augenscheinlich nicht bei allen Lebensmittelunternehmern aus, um sie von gewinnträchtigen Verstößen gegen lebensmittelrechtliche Vorschriften abzuhalten. Vor diesem Hintergrund gibt der vorliegende Beitrag mit Blick auf die Ernährungswirtschaft einen Überblick über Regulierungsanforderungen, -möglichkeiten und -ansätze. Für eine effektive und kosteneffiziente Prävention sind smarte Regulierungsansätze erforderlich, die nicht nur dysfunktionale Effekte wie Crowding-Out und Reaktanz vermeiden, sondern in der Lage sind, intrinsische Motive und extrinsische Anreize zur Regelbefolgung gleichzeitig zu stärken (Crowding-In). Insbesondere Name-and-Shame erscheint hierfür aus verhaltensökonomischer Sicht geeignet zu sein.A series of food scandals has indicated lately that misdirected economic incentives, in conjunction with a lack of norms to abide by the law, induce non-compliance with food regulations and thus behavioural food risks. Against this background, we outline both the specific need for regulation and the available regulatory approaches in the food sector. An effective and cost-efficient prevention of rule-breaking behaviour requires smart regulation. Smart approaches to regulation not only avoid the dysfunctional effects of crowding-out and reactance but simultaneously enhance intrinsic motives and extrinsic incentives to comply (crowding-in). From a behavioural economic point of view, name-and-shame has a good chance of qualifying as "smart"
Understanding and Managing Behavioural Risks -The Case of Food Risks Caused by Malpractice in Poultry Production
No full textThe probability that actors in economic relationships break rules increases with the profits they thus expect to earn. It decreases with the probability and level of short- and long-term losses resulting from disclosure. It also decreases with the level of social context factors and intrinsic values which shield actors from yielding to economic temptations. This paper assesses the relative merits of various scientific approaches concerned with risks in economic relationships and outlines their contribution to the study of opportunistic rule-breaking. Since the identification of (misdirected) economic incentives faced by firms and individuals represents the starting point for a systematic analysis of opportunism in any field, we also outline a microeconomic approach that systematically provides this crucial information. The approach is applied to the problem of food quality and safety threatened by opportunistic malpractice of food business operators. Its essentials are illustrated through a study which systematically searches for the temptations to break production-related rules in the poultry industries.asymmetric information, control theories, economic misconduct, game theory, moral hazard, principal-agent model, opportunism, protective factors, relational risks, Food Consumption/Nutrition/Food Safety, A13, K32, K42,
Using business simulation games in regulatory impact analysis - the case of policies aimed at reducing nitrogen leaching
No full textIn the past, regulatory impact analysis was predominantly based on the rational-choice-assumption of a completely informed and exclusively profit-maximizing homo oeconomicus. Real economic actors, however, are multiple-goal and boundedly rational decision-makers. An exclusive reliance on rational-choice models therefore generates the risk that both the pace and the type of behavioural adaptations to changing institutional environments are misjudged. Against this background, this article addresses three questions. First, can we use business simulation games as a convincing but low-cost experimental tool for policy analysis? Second, how do intentionally varied nitrogen extensification schemes impact the behaviour of students who participate in an explorative business simulation study? Third, do nitrogen reduction policies that are framed as voluntary as opposed to prescriptive schemes have a different impact on behaviour even if they lead to the same profits respectively? In our business simulation game, the student-participants take the role of farmers who are confronted with different policy measures aimed at reducing nitrogen loads. The student-farmers react very differently to different measures even though all measures have an identical impact on profitability. This is an indication that the behavioural changes that can be achieved per Euro of the taxpayers' money, and therefore the cost efficiency (and smartness) of regulatory measures, are contingent on their specific design
Optimizing Production Decisions Using a Hybrid Simulation-Genetic Algorithm Approach
No full textMathematical programming has for a long time been recognized as a powerful tool. Despite its capacity for solving constrained optimization problems under uncertainty, some methodological obstacles have persisted over the years. The main problem is that the eventually complex results of an unbiased statistical analysis (multiple correlated stochastic variables with different distributions and nonadditive links between) cannot be adequately accounted for within minimization of total absolute deviation (MOTAD) or expected value-variance (EV) models that rely on the algorithmic determination of the variability measure. In this paper, we develop a methodological hybrid consisting of Monte Carlo simulation and genetic algorithms: the Monte Carlo simulation facilitates the easy representation of diverse stochastic processes and correlation, and the genetic algorithm ensures that the optimization procedure remains applicable even in the case of complex stochastic information. This hybrid approach is applied to the production-planning problem of a German crop farm. Variant calculations are used to account for the unknown risk attitude of the farmer. Model results demonstrate that optimized production programs and expected total gross margins are not only highly sensitive to the risk attitude, but also to the stochastic processes that are estimated (or assumed) for various activities. We furthermore find evidence that the hybrid approach is able to generate considerable improvement in farm-program decisions and outperforms planning models that assume static distributions.German Research Foundation (DFG
Investment planning under uncertainty and flexibility: the case of a purchasable sales contract
No full textInvestment decisions are not only characterised by irreversibility and uncertainty but also by flexibility with regard to the timing of the investment. This paper describes how stochastic simulation can be successfully integrated into a backward recursive programming approach in the context of flexible investment planning. We apply this hybrid approach to a marketing question from primary production which can be viewed as an investment problem: should grain farmers purchase sales contracts which guarantee fixed product prices over the next 10 years? The model results support the conclusion from dynamic investment theory that it is essential to take simultaneously account of uncertainty and flexibility.dynamic programming, flexibility, investment, sales contract, stochastic simulation, uncertainty, Agricultural Finance, Risk and Uncertainty,
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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