Choosing on Influence

Interaction, the act of mutual influence between two or more individuals, is an essential part of daily life and economic decisions. Yet, micro-foundations of interaction are unexplored. This paper presents a first attempt to this purpose. We study a decision procedure for interacting agents. According to our model, interaction occurs since individuals seek influence for those issues that they cannot solve on their own. Following a choice-theoretic approach, we provide simple properties that aid to detect interacting individuals. In this case, revealed preference analysis not only grants the underlying preferences but also the influence acquired. Our baseline model is based on two interacting individuals, though we extend the analysis to multi-individual environments.

Bilateral oligopoly and quantity competition

Bilateral oligopoly is a strategic market game with two commodities, allowing strategic behavior on both sides of the market. When the number of buyers is large, such a game approximates a game of quantity competition played by sellers. We present examples which show that this is not typically a Cournot game. Rather, we introduce an alternative game of quantity competition (the market share game) and, appealing to results in the literature on contests, show that this yields the same equilibria as the many-buyer limit of bilateral oligopoly, under standard assumptions on costs and preferences. We also show that the market share and Cournot games have the same equilibria if and only if the price elasticity of the latter is one. These results lead to necessary and sufficient conditions for the Cournot game to be a good approximation to bilateral oligopoly with many buyers and to an ordering of total output when they are not satisfied.

Markets and linguistic diversity

The choice of language is a crucial decision for firms competing in cultural goods and media markets with a bilingual or multilingual consumer base. To the extent that multilingual consumers have preferences over the intrinsic characteristics (content) as well as over the language of the product, we can examine the efficiency of market outcomes regarding linguistic diversity. In this paper, I extend the spokes model and introduce language as an additional dimension of product differentiation. I show that: (i) if firms supply their product in a single language (the adoption model) then the degree of linguistic diversity is inefficiently low, and (ii) if some firms supply more than one linguistic version (the translation model) then in principle the market outcome may exhibit insufficient or excessive linguistic diversity. However, excessive diversity is associated to markets where the fraction of products in the minority language is disproportionately high with respect to the relative size of the linguistic minority.

Decision analysis for the genotype designation in low-template-DNA profiles

What genotype should the scientist specify for conducting a database search to try to find the source of a low-template-DNA (lt-DNA) trace? When the scientist answers this question, he or she makes a decision. Here, we approach this decision problem from a normative point of view by defining a decision-theoretic framework for answering this question for one locus. This framework combines the probability distribution describing the uncertainty over the trace's donor's possible genotypes with a loss function describing the scientist's preferences concerning false exclusions and false inclusions that may result from the database search. According to this approach, the scientist should choose the genotype designation that minimizes the expected loss. To illustrate the results produced by this approach, we apply it to two hypothetical cases: (1) the case of observing one peak for allele xi on a single electropherogram, and (2) the case of observing one peak for allele xi on one replicate, and a pair of peaks for alleles xi and xj, i ≠ j, on a second replicate. Given that the probabilities of allele drop-out are defined as functions of the observed peak heights, the threshold values marking the turning points when the scientist should switch from one designation to another are derived in terms of the observed peak heights. For each case, sensitivity analyses show the impact of the model's parameters on these threshold values. The results support the conclusion that the procedure should not focus on a single threshold value for making this decision for all alleles, all loci and in all laboratories.

Perceptions of Europe in political and economic elites: a geographical compared analysis of Germany, Spain and Poland

Elite perceptions about Europe are a very important point in order to understand the current European integration process, as well as the future perspectives for the continent. This study makes a comparison between the perceptions which political and economical elites in some European countries have about the European Union process and its mechanisms. The main goal is to identify the differences in positions of each type of elites, as well as the variations among three key countries. The database built thanks to the INTUNE (Integrated and United? A quest for Citizenship in an ¨ever closer Europe¨) Project Survey on European Elites and Masses, funded by the Sixth Framework Programme of the EU [Contract CIT 3-CT-2005-513421] have being used. The questionnaire was applied between February and May 2007, in a total of 18 European countries. The national teams got a total of almost 2000 valid responses at European level. In the analysis we have showed some general descriptive statistics about the perception of Europe taking as a reference two dimensions of the INTUNE project: identity (attachment to the national level, the meaning of being a truly national, and the threats from Turkey that EU is facing at this moment) and representation (trust in European and national institutions, preferences for a national or an European army). The results are presented distinguishing between political (national MP’s in low chambers) and economical elites (presidents of corporations, general managers…) and, at the same time, among three countries: Germany as an original member of the European Union; Spain, incorporated in 1986; and a new member, Poland, joining the EU in 2004.

The Division problem with voluntary participation

The division problem consists of allocating a given amount of an homogeneous and perfectly divisible good among a group of agents with single-peaked preferences on the set of their potential shares. A rule proposes a vector of shares for each division problem. The literature has implicitly assumed that agents will find acceptable any share they are assigned to. In this paper we consider the division problem when agents' participation is voluntary. Each agent has an idiosyncratic interval of acceptable shares where his preferences are single-peaked. A rule has to propose to each agent either to not participate or an acceptable share because otherwise he would opt out and this would require to reassign some of the remaining agents' shares. We study a subclass of efficient and consistent rules and characterize extensions of the uniform rule that deal explicitly with agents' voluntary participation.

On Strategy-proofness and symmetric single-peakedness

We characterize the class of strategy-proof social choice functions on the domain of symmetric single-peaked preferences. This class is strictly larger than the set of generalized median voter schemes (the class of strategy-proof and tops-only social choice functions on the domain of single-peaked preferences characterized by Moulin (1980)) since, under the domain of symmetric single-peaked preferences, generalized median voter schemes can be disturbed by discontinuity points and remain strategy-proof on the smaller domain. Our result identifies the specific nature of these discontinuities which allow to design non-onto social choice functions to deal with feasibility constraints.

Work values, endogenous sentiments and redistribution

We examine the interactions between individual behavior, sentiments and the social contract in a model of rational voting over redistribution. Agents have moral "work values". Individuals' self-esteem and social consideration of others are endogenously determined comparing behaviors to moral standards. Attitudes toward redistribution depend on self-interest and social preferences. We characterize the politico-economic equilibria in which sentiments, labor supply and redistribution are determined simultaneously. The equilibria feature different degrees of "social cohesion" and redistribution depending on pre-tax income inequality. In clustered equilibria the poor are held partly responsible for their low income since they work less than the moral standard and hence redistribution is low. The paper proposes a novel explanation for the emergence of different sentiments and social contracts across countries. The predictions appear broadly in line with well-documented differences between the United States and Europe.

Preference intensities and risk aversion in school choice: a laboratory experiment

We experimentally investigate in the laboratory two prominent mechanisms that are employed in school choice programs to assign students to public schools. We study how individual behavior is influenced by preference intensities and risk aversion. Our main results show that (a) the Gale-Shapley mechanism is more robust to changes in cardinal preferences than the Boston mechanism independently of whether individuals can submit a complete or only a restricted ranking of the schools and (b) subjects with a higher degree of risk aversion are more likely to play "safer" strategies under the Gale-Shapley but not under the Boston mechanism. Both results have important implications for the efficiency and the stability of the mechanisms.

Best practice in the management of mild-to-moderately active ulcerative colitis and achieving maintenance of remission using mesalazine.

Optimizing treatment goals in ulcerative colitis requires recognizing the needs of patients. It is increasingly recognized that adapting treatment strategies aligned with patient needs can improve patient compliance and consequently minimize relapse rates. Tailoring of treatment strategies can improve not only patient quality of life, and decrease the number harmed by adverse events from more potent drugs, but can also save valuable healthcare costs by avoiding high-cost treatment interventions associated with acute ulcerative colitis. This review will consider several elements of mesalazine management from the patient perspective based on a range of clinical and patient-focused evidence. By highlighting patient preferences in disease management it is envisaged that this review will aid physicians to optimize treatment decisions with the different mesalazine preparations available.

The Potential for Dispersal of Onchocerciasis in Ecuador in Relation to the Distribution of the Vector Simulium exiguum (Diptera:Simuliidae)

The future dispersal of onchocerciasis in Ecuador is dependent on the distribution of cytotypes of the vector species complex Simulium exiguum. Over the last 14 years, collections of larvae have been made from over 25 rivers, between 80-1600 m altitude, from various sites on both sides of the Andes. Analysis of larval polytene chromosomes was used to determine the distributions of each cytotype. On the western side of the Andes, the Cayapa cytotype (the only cytotype directly incriminated as a vector) has a distribution from Santo Domingo de los Colorados northwards. The Quevedo and Bucay cytotypes occur from Santo Domingo de los Colorados southwards. On the eastern side of the Andes, the Aguarico cytotype occurs in the Rio Aguarico and a new cytotype is present in the tributaries of the Rio Napo. Whether the disease will spread south of Santo Domingo and on the eastern side of the Andes depends on vector capacity of the cytotypes and the dispersal patterns of individuals infected with onchocerciasis. At present the Aguarico, Bucay and Quevedo cytotypes are known to be efficient hosts, but their biting preferences and biting densities have not yet been evaluated

Party competition in regional elections: a framework for analysis

Whilst scholars have long recognised that processes of decentralisation create new regional arenas where distinct patterns of party competition are likely to emerge, there has been little systematic analysis of the dynamics of such competition. This working paper thus proposes a framework for analysing party competition between regional branches of state-wide parties, and autonomist parties, in regional arenas. Firstly, the different strategies political parties may adopt in response to their perceptions of voter preferences and to the strategies pursued by their competitors are identified. Secondly, different factors that impact on parties' strategic choices, and which may constrain a party's ability to select electorally optimal strategies in a given political context, are proposed.

Sincere Lobby Formation

This paper analyzes endogenous lobbying over a unidimensional policy issue. Individuals differ in policy preferences and decide either to join one of two opposite interest lobbies or not to take part in lobbying activities. Once formed, lobbies make contributions to the incumbent government in exchange for a policy favor as in a common-agency model. A "sincere-lobby-formation" condition for equilibrium is introduced: an individual joins a lobby if their gain from the policy change that this lobby might achieve exceeds a contribution fee. Thus, an equilibrium occurs only if no lobby member would prefer their lobby to cease to exist. I show the existence of an equilibrium with two organized lobbies. Individuals with more extreme preferences are more likely to join lobbying activities. I fi…nd that lobbying somewhat moderates the government's preferences, i.e., it shifts the …final policy in favor of individuals who are initially disadvantaged by the government's pro- or anti-policy preferred position. Under a utilitarian government, however, lobbying does not affect the fi…nal policy, and political competition results in a socially optimal outcome. JEL classi…cation: D72. Keywords: Sincere lobby formation; common agency; endogenous lobbying.

Work, risk and health: differences between immigrants and natives in Spain

We analyze the impact of working and contractual conditions, particularly exposure to job risks, on the probability of acquiring a disability. We postulate a model in which this impact is mediated by the choice of occupation, with a level of risk associated to it. We assume this choice is endogenous, and that it depends on preferences and opportunities in the labour market, both of which may differ between immigrants and natives. To test this hypothesis we use data from the Continuous Sample of Working Lives of the Spanish SS system. It contains individual, job and firm information of over a million workers, including a representative sample of immigrants. We find that risk exposure increases the probability of permanent disability by 5.3%; temporary employment also influences health. Migrant status -with differences among regions of origin- significantly affects both disability and the probability of being employed in a risky occupation. Most groups of immigrants work in riskier jobs, but have lower probability of becoming disabled. Nevertheless, our theoretical hypothesis that disability and risk are jointly determined is not valid for immigrants: i.e. for them working conditions is not a matter of choice in terms of health.