WICKEDNESS IN SOCIAL CHOICE

In an article from 1973, Rittel and Webber distinguished between ‘tame’ or ‘benign’ problems on the one hand and ‘wicked’ problems on the other. The authors argued that wicked problems occur in nearly all public policy issues. Since different groups adhere to different value-sets, solutions can only be expressed as better or worse. By no means can they be viewed as definitive or objective. In this paper we consider, from this very angle, the theory of social choice which is about the aggregation of individual preferences with the aim to derive a consistent social preference. We show that collective choice offers wicked problems of various types which differ in their degree of severity. We hereby concentrate on welfare functions and voting schemes of different kinds and discuss these in the light of various criteria such as Arrow's independence condition, Condorcet consistency, monotonicity, manipulability, and other properties.     

Effort maximization in asymmetric contest games with heterogeneous contestants

Contest rules are set up by administrators who frequently have discretionary power in specifying the details of these rules, i.e., they can bias the contest rules toward specific contestants in order to further their prime objective. We derive the optimal bias of the contest rule for a contest administrator, who is interested in maximizing the total efforts expended in the contest. The solution is obtained in closed form for a widely used class of n-person contest games. Setting the optimal bias has important implications: (i) there is never exclusion of strong players, instead there is (endogenously induced) inclusion of weak contestants; (ii) the contest administrator will optimally level the playing field by encouraging weak contestants, but he will not equalize the contestants’ chances unless they are identical; and (iii) at least three contestants will be active in equilibrium of the optimal contest, irrespective of heterogeneity.     

Technological regimes and demand structure in the evolution of the pharmaceutical industry

This paper examines how the nature of the technological regime governing innovative activities and the structure of demand interact in determining market structure, with specific reference to the pharmaceutical industry. The key question concerns the observation that—despite high degrees of R&D and marketing-intensity—concentration has been consistently low during the whole evolution of the industry. Standard explanations of this phenomenon refer to the random nature of the innovative process, the patterns of imitation, and the fragmented nature of the market into multiple, independent submarkets. We delve deeper into this issue by using an improved version of our previous “history-friendly” model of the evolution of pharmaceuticals. Thus, we explore the way in which changes in the technological regime and/or in the structure of demand may generate or not substantially higher degrees of concentration. The main results are that, while technological regimes remain fundamental determinants of the patterns of innovation, the demand structure plays a crucial role in preventing the emergence of concentration through a partially endogenous process of discovery of new submarkets. However, it is not simply market fragmentation as such that produces this result, but rather the entity of the “prize” that innovators can gain relative to the overall size of the market. Further, the model shows that emerging industry leaders are innovative early entrants in large submarkets.     

An efficient nonparametric estimator for models with nonlinear dependence

We provide a convenient econometric framework for the analysis of nonlinear dependence in financial applications. We introduce models with constrained nonparametric dependence, which specify the conditional distribution or the copula in terms of a one-dimensional functional parameter. Our approach is intermediate between standard parametric specifications (which are in general too restrictive) and the fully unrestricted approach (which suffers from the curse of dimensionality). We introduce a nonparametric estimator defined by minimizing a chi-square distance between the constrained densities in the family and an unconstrained kernel estimator of the density. We derive the nonparametric efficiency bound for linear forms and show that the minimum chi-square estimator is nonparametrically efficient for linear forms.     

Potron and the Perron–Frobenius Theorem

Maurice Potron is an important precursor of the study of linear models of production and, in particular, of input–output analysis. We show that, contrary to Abraham-Frois and Lendjel's interpretation which we consider as unfaithful to Potron's model, there is a clear connection between his theory and the Perron-Frobenius theorem.     

Triangulation: Validity and empirically-based hypothesis construction

The essay focuses on the opportunities and strengths of a multi-method approach, widely called methodological triangulation, in which different investigative methods are applied to one research object. In practice, this can be realized with the coupling of quantitative structural data concerning the life course and the interpretation and evaluation of life course data collected with qualitative methods. This approach is examined in order to shed light on the problem that research findings often show different phenomena and not the different aspects of one phenomenon. The discussion of the relationships of the findings to one another (congruent, complementary or divergent) shows that in this context a multi-method approach can nevertheless be used to increase validity and to test hypotheses. Further, its particular strengths are the empirically induced modification of existing models and theories, as well as the development of new explanations.     

Pitfalls of Normal-Gamma Stochastic Frontier Models

Although conceptually pleasing, normal-gamma frontier models lead to difficult estimation problems. It is shown here that unless the sample size reaches several thousands of observations the shape parameter of the gamma density is hard to estimate, and that this carries over to estimates of the stochastic frontier, the individual inefficiencies, and the allocation of the overall variance to the stochastic frontier and to the inefficiencies.     

Return migration, wage differentials, and the optimal migration duration

In simple static models, migration increases with the wage differential between host- and home-country. In a dynamic framework, and if migrations are temporary, the size of the migrant population in the host country depends also on the migration duration. This paper analyses optimal migration durations in a model which rationalises the decision of the migrant to return to his home country, despite persistently higher wages in the host country. The analysis shows that, if migrations are temporary, the optimal migration duration may decrease if the wage differential grows larger. Using micro data for Germany, the second part of the paper provides empirical evidence which is compatible with this hypothesis.     

Investment Decisions,Financial Flows,and Self‐Enforcing Contracts*

This article studies the role of risk sharing in dynamic credit relationships that are secured by physical collateral. It is shown that, when borrowers and lenders cannot commit not to terminate relationships (through default in the first case and liquidation in the second), overinvestment is optimal. Overinvestment facilitates risk sharing in this context: It occurs in expectation of periods in which lenders are unwilling to supply all the funds necessary to achieve complete risk sharing. Typically, overinvestment happens when investment decreases; it slows down the pace at which the capital stock is reduced and therefore results in production smoothing.