Competitive supply behavior when price information is fuzzy

The theory of fuzzy sets is applied to the output decisions of a price-taking firm facing imprecise information about expected future prices. Accepting risk resulting from the randomness of prices, the manager is interested in expected profits only. Since the set of possible expected-price vectors is fuzzy, a suitable defuzzification strategy is defined in analogy to the pessimism-optimism index proposed by L. Hurwicz. It depends on the manager's willingness to accept surprises resulting from a deviation of the true expected prices from the values that guided output decisions. Despite a linear cost function, well specified solutions to the optimization problem are possible without resorting to capacity constraints.     

False Discoveries und Fehlinterpretationen wissenschaftlicher Ergebnisse

High-quality science communication to the public depends to a large extent on the way research findings are translated into comprehensible language and common speech. In this communicative process, a reasonable evaluation of the trustworthiness of empirical findings, based on an adequate interpretation of statistical analyses, is absolutely crucial. This paper’s authors argue that the credibility of science is jeopardised by two compromising developments within science itself: on the one hand, an inflation of ostensible empirical evidence related to misuses and misinterpretations of the concept of statistical significance, and, on the other, a sensationalist overvaluation of the results of single studies instead of an adequate representation of the available body of evidence in a given scientific field.     

The Headmaster Ritual: The Importance of Management for School Outcomes

We estimate the impact of individual principals on school outcomes by using panel data that allow us to track principals over time. We find that individual principals have a substantive impact on school policies, working conditions, and student outcomes. In particular, students who attend a school that has a one standard deviation better principal improve their achievement by between 0.05 and 0.1 standard deviations. Despite rich background information on principals, it is difficult to characterize successful management, suggesting that innate skills are central. We find that the scope for discretion is larger among voucher schools and in areas with school competition.     

Response style corrected market segmentation for ordinal data

Survey data collected for market segmentation studies is typically ordinal in nature. As such, it is susceptible to response styles. Ignoring response styles can lead to market segments which do not differ in beliefs, but merely in how segment members use survey answer options and which possibly occur in addition to the belief segments. We propose a finite mixture model which simultaneously segments and corrects for response styles, permits heterogeneity in both beliefs and response styles, accommodates a range of different response styles, does not impose a certain relationship between the response style and belief segments, and is suitable for ordinal data. The performance of the model is tested using both artificial and empirical survey data.     

Modelling purchases as a function of advertising and promotion

This article describes the preliminary studies of the effect of advertising and promotion on purchases. The British single-source database Adlab has been the basis for this study of advertising and promotion effectiveness. The ST AS measure and logit modelling have been used to estimate the effect of advertising. The results from the two measures have been compared to determine the extent to which the two measures give occasion for the same conclusions. To indicate the accuracy of the two measures, their respective levels of significance have been studied. Two logit models have been estimated; one only includes the effect of TV exposure, while the other also includes the effect of promotions. The results from the two logit models are compared to determine which model gives the most accurate estimate of the effect of advertising. When comparing the results from the STAS measure with the parameter estimates from the second logit model, it is found that these two different measures largely lead to similar conclusions. Suggestions for further research and developments of the models are given.