The robustness of PREFMAP-2

A simulation study on the possibilities to reproduce a ‘true’ rank order of preferences and an underlying configurational structure of weighted distances between ideal points and real stimulus objects by PREFMAP-2 (Phase 2) is performed. Eleven hypotheses are evaluated with respect to three measures of reproduction quality. The results are mainly derived from three-way analyses of variance. Input rank orders can be reproduced quite well. This is not true for the underlying configurational designs, from which input rank orders are thought to be derived. Cluster designs, small numbers of stimulus objects and error are main effects to limit the quality of the results.     

On Social Statement Spaces

In this fundamental draft we shall introduce the concept of social propositional spaces as a general notion of social science and in particular language, logic and methodology. This should help us bridge an old gap between extension and cognition, or said in more specific words, between space as conceived in mathematics or physics and space as is brought in by social location, by the meaning of predicates, their explanation and logic. ¹ We shall not rely on the idea of factor analysis where some “main components” are fit into the data. Because the notion of euclidean normalization and orthogonality, in this context, is a bit artificial. We first show how combinatorial manifolds of statements can be represented in finite vector spaces over the Galois field F₂. This space which we denote as logic statement space can be spanned by generators of alternating codes. In this way the old concepts of truth tables and interaction attributes can be linked to informatics and in particular code theory and geometry. Extending the logic statement space onto a real vector space by mapping units of the finite rings onto units of the real rings we obtain logistic statement spaces. It turns out that vectors in logistic statement spaces represent cross-tables of logits connected with logistic regression analysis. As a completion of the theory we show that the logit is the first derivative of entropy with respect to probability.     

Product differentiation and competitive pressure

This paper compares the commonly used linear demand model introduced by Bowley (The mathematical groundwork of economics, Oxford University Press, Oxford, 1924) with the specification of Shapley and Shubik (Kyklos 22:30?C44, 1969). The latter has the advantage that aggregate demand does not depend on a parameter that measures the degree of product differentiation. This allows to interpret variations in the degree of product differentiation as changes in competitive pressure because these changes can influence aggregate demand only through changes in equilibrium prices and quantities. The consequences of the alternative specifications are made explicit with two applications. In both cases the different specifications yield substantial changes in important results in industrial economics.     

Return on Quality Improvements in Search Engine Marketing

In search engine marketing, such as on Google, advertisements' ranking and prices paid per click result from generalized, second-price, sealed bid auctions that weight the submitted bids for each keyword by the quality of an advertisement. Conventional wisdom suggests that advertisers can only benefit from improving their advertisement's quality. With an empirical study, this article shows that quality improvements have complex effects whose returns are actually unclear: 5% of all quality improvements to an advertisement lead to higher prices (measured by price per click) per keyword, 100% to a higher number of clicks, 53% to higher costs for search engine marketing, and 37% to lower profits. Quality improvements lead to higher weighted bids, which only lower prices if they do not improve the ranking of the advertisement. Otherwise, better ranks likely lead to higher prices. A decomposition method can disentangle these effects and explain their effects on search engine marketing costs and profits. Finally, the results indicate that advertisers benefit if they lower their bids after improvements to advertising quality.     

Engagement in European social dialogue: an investigation into the role of social partner structural capacity

Despite the importance of social dialogue for the European social model, there has been little attention to the factors that account for social partner engagement with European social dialogue. On the basis of data from 28 European sectoral social dialogue committees, this article investigates structural factors that account for the conclusion of European sectoral social dialogue agreements. It is found that actors' organisational density is a necessary but not sufficient factor for successful European social dialogue and four different categories of sectoral social partner engagement with European social dialogue are identified.