A Social Choice Trade-off Between Alternative Fairness Concepts: Solidarity versus Flexibility

In this paper, we define simple measures of two properties that social choice functions may embody in different degrees in public goods environments. First, a measure of solidarity is proposed such that Thomson's (1990) replacement monotonicity property is a particular case in which the full amount of solidarity is required. Secondly, we introduce a measure of the degree of flexibility of a social choice function and prove that a trade-off in Campbell and Kelly's (1993) sense exists between both properties. More solidarity can only be achieved in exchange of less flexibility of the decision rule. When we restrict ourselves to the family of voting schemes called generalized Condorcet winner solutions, introduced by Moulin (1980), we find the exact trade-off and we can easily find the degrees of fulfillment of both properties, which amount to some generalization of the idea of ''qualified majority''.Single-peaked preferences, solidarity, welfare domination under preference replacement

The Impossibility of Strategy-Proof Clustering.

Clustering methods group individuals or objects based on information about their similarity or proximity. When the raw information to generate the clusters cannot be easily observed or verified, the clusters designer must rely on information reported on individuals behind the observations. When individuals receive utility from a public decision taken with aggregated data within each own's cluster and have single-peaked preferences, we prove that there do not exist cluster methods such that truth-revealing behavior is always a dominant strategy.clustering methods, strategy-proofness, single-peaked preferences, public decision.

Strategy-Proof Estimators for Simple Regression

In this paper we propose a whole class of estimators (“clockwise repeated median estimators” or CRM) for the simple regression model that are immune to manipulation by the agents generating the data. Although strategic considerations affecting the stability of the estimated parameters in regression models have already been studied (the Lucas critique), few efforts have been made to design estimators that are incentive compatible. We find that some well-known robust estimators proposed in the literature like the resistant line method are included in our family. Finally, we also undertake a Monte Carlo study to compare the distribution of some estimators that are robust to data manipulation with the OLS estimators under some specific data manipulation process.strategy-proofness, single-peaked preferences, robust regression, data contamination.

Dominant Strategies Implementation of the Critical Path Allocation in the Project Planning Problem

In this paper we propose to analyze the economic problem of allocating tasks on time in order to finish a complex project when information about tasks' duration and predating sequences of tasks is privately owned by the agents that undertake each task. In order to achieve the efficient allocation of tasks -using the well-known Critical path method in the Operations Research literature-, the planner must design the appropriate incentives and compensations to the agents based on the reported information. We show the existence of mechanisms that implement in dominant strategies the efficient allocation of tasks on time. When we further add new desirable properties like individual rationality, an impossibility result emerges.Critical path, PERT, Dominant strategies, implementation, tasks allocations, strategy-proofness, individual rationality.

Dominant Strategies Implementation when Compensations are Allowed:a Characterization Fundación

Dominant strategies truthful implementation of flexible social objectives involves the ability of the planner to alter the individual incentives in such a way that the externality imposed on society by each agent reporting a given type is fully internalized in the agent’s final payoff. In other words, the agents’ objective function must mimic the social objectives. We find that our main result is robust enough to explain why well-known mechanisms like Groves’s transfers work in some contexts while some other social objectives are not implementable in dominant strategies.Individual decisiveness, compensation mechanisms, dominant strategies.

Solidarity in Terms of Reciprocity*

In this paper we introduce a new concept of solidarity in terms of reciprocity and characterize the set of social choice functions that are reciprocate (in both a strong and a weak sense), anonymous and efficient in a standard public good provision model when the agents have single-peaked preferences on the amount of the good provided. The resulting procedures are the well-known Generalized Condorcet Winner Solutions, and therefore, we provide an alternative characterization of that class of social choice functions based in new ethical properties regarding solidarity.Single-peaked preferences, solidarity, welfare domination under preference replacement.

Compensation schemes in collective decision making

Consultable des del TDXTítol obtingut de la portada digitalitzadaLa presente memoria consiste en cuatro artículos independientes de la Teoría de la Elección Social y el diseño de mecanismos. Los dos primeros capítulos están especialmente relacionados, pues comparten el objetivo común de relajar una idea de solidaridad llamada "monotonía de reemplazamiento" o dominancia de bienestar ante cambios de prefefencias propuesta en literatura por Moulin (1987) y Thomson (1993, 1995a, 1995b). Los capítulos 2 y 3 comparten el mismo modelo básico de provisión de un bien público en el que no se permiten compensaciones. Se supone que los agentes tienen preferencias unimodales definidas sobre un único bien unidimensional e investigamos y superamos los pocos procedimientos de elección social que son monotónicos de reemplazamineto en este modelo. El capitulo 2 introduce una propiedad de solidaridad nueva en términos de reciprocidad en este contexto. Esta propiedad permite una clase de procedimientos de elección social mas rica que la que se obtiene con en concepto de solidaridad de Thomson. Nuestra propuesta refleja de alguna manera un concepto de solidaridad introspectivo. Se requiere que cuando alguien cambia de preferencias y la elección social se altera, todos los restantes agentes pueden estar seguros de que el mismo agente que cambió habría sido afectado de forma recíproca si ellos hubieran cambaido de la misma forma. Asimismo se ofrecen caracterizaciones de las reglas que satisfacen la reciprocidad en una versión fuerte y una débil. El capitulo 3 relaja la monotonía de reemplazamiento de una manera mas directa, entendiendo la solidaridad en el sentido de la proporción de agentes que ganan o pierden juntos cuando alguien cambia de preferencias. Se demuestra que la solidaridad entra en conflicto directo con otros conceptos de justicia. De hecho, las elecciones mas centristas o igualitarias están asociadas con el grado de solidaridad mas reducido. Aplicando la "teoría de arbitrajes" de Campbell y Kelly (1993), proponemos medidas razonables tanto de la solidaridad como de la rigidez de los procedimientos elección social y se encuentra un menú de reglas de votación que incorpora los diversos grados de ambas propiedades deseables. Los capítulos 4 y 5 tratan del problema de encontrar mecanismos compatibles con incentivos en dos contextos de producción diferentes cuando se permiten compensaciones para inducir el comportamiento honesto. En el capitulo 4 tratamos con un problema de implementación en el que el esquema de compensaciones no es parte de las alternativas factibles, sino discreccional del planificador. En este marco, suponemos que el planificador o principal posee la habilidad de diseñar parcialmente la forma funcional del objetivo final de la división para incentivar su comportamiento honesto en el contrato ofrecido a ésta. En el capítulo 5 tratamos del problema del diseño de un contrato entre los miembros de una compleja organización productiva-como las divisiones dentro de una empresa- para incentivarlos al comportamiento honesto en presencia de información privada acerca de parte de las tecnologías. En particular, proponemos un modelo simple de asignación de tareas conocido en la literatura de programación de redes como Método del Camino Crítico CPM o PERT. Las divisiones tienen que ejecutar tareas en el tiempo que deben ser asignadas en una red. Se prueba la existencia en este contexto de mecanismos anónimos a prueba de estrategias que son eficientes en el sentido de minimizar el tiempo total empleado para acabar el projecto y que también pueden equilibrarse, obteniéndose así la eficiencia completa.This memory consists of four independent essays on Social Choice Theory and Mechanism Design. The first two chapters are particularly related since they share the common aim of relaxing an idea of solidarity called replacement monotonicity or welfare-domination under preference-replacement proposed in the literature by Moulin (1987) and Thomson (1993, 1995a, 1 995b). Chapters 2 and 3 share the same basic model of public good provision in which no monetary compensations are allowed. Agents are assumed to have single-peaked preferences defined on a single uni-dimensional good and we try to investigate and overcome the limited number of Social Choice procedures that are replacement monotonic within this setup. Chapter 2 introduces a new property of solidarity in terms of reciprocity for these environments. This property allows for a richer class of social choice procedures than Thomson's solidarity concept of welfare-domination under preference-replacement. Our proposal reflects somehow an introspective concept of solidarity. It requires that when somebody changes his preferences and the social decision is altered, all the remaining agents can be sure that the same agent who has actually changed would have been affected in a reciprocal way if they had changed likewise. Characterizations of the rules satisfying reciprocity in both a strong and a weak version are therefore provided. Chapter 3 relaxes replacement monotonicity in a more direct way, understanding solidarity in the sense of the proportion of society gaining or losing together when somebody changes his preferences. It is demonstrated that solidarity is in direct conflict with other fairness criteria. Actually, achieving centrist or equitable outcomes leads to the smallest possible solidarity degree. Applying Campbell and Kelly's (1993) Trade-offTheory, we propose reasonable mesures of both solidarity and rigidity of social choice procedures and a menu of voting procedures is found to embody different degrees of both desirable properties. Chapters 4 and 5 deal with the problem of finding strong incentive compatible mechanisms in two different production contexts when compensations to induce truthful behavior are allowed. In Chapter 4 we deal with an implementation problem where the compensation sheme is not part of the feasible alternatives, but discretional to the planner. Within this framework, we assume that the planner or principal have the ability to partially design the functional form of the division s final payoffs to incentive their truthful behavior in the contract offered to the divisions. In Chapter 5 we deal with the same problem of designing a contract between the members of a complex productive organization -say divisions within a firm- to give incentives for truthful behavior in the presence of private information about parts of the technologies. In particular, we propose a simple task allocation model known in the network programming literature as the Critical Path Method, CPM or PERT. Divisions have to undertake time-consuming tasks that have to be allocated in a network. We prove the existence in this environment of anonymous and strategy-proof mechanisms that are efficient in the sense of minimising the total amount of time employed in finalising the project and can also be balanced, so full efficiency is achieved

Incentives for prosocial behavior under reputation persistence and policy lags

In this paper we show that a policy based on incentives to promote prosocial activities can be counterproductive in a context where the agents’ reputation exhibits persistence over time and there exists a time lag between announcement of the policy and implementation. Reputation persistence in our model means that the reputation gained in past periods constrains the possibilities of changing reputation in the future. We present a two-period model in which agents use prosocial activities to signal their degree of altruism. If a subsidy is established for the second period, the set of agents that undertake social activities in that period enlarges. This worsens the reputation of the most altruistic agents, some of whom then react by decreasing their involvement in prosocial activities in the first period. We identify a condition under which subsidies cause a decrease in the global supply of pro-social activities

The Lazarillo’s game: Sharing resources with asymmetric conditions

[EN]The Lazarillo of Tormes' picaresque novel introduces a story where two subjects sequentially extract (one, two or three) tokens from a common pool in an asymmetric information framework (the first player cannot observe her partners' actions). By introducing a reward for both subjects in case that in every period at least one subject had taken one single token, we define an interesting coordination game. We conduct an experiment with 120 undergraduate students to study their behavior in this framework. We find that if the second player is allowed to take more tokens than her partner, then the frequency of cooperators does not seem to be affected by the informational asymmetry. Nevertheless, this asymmetry (i) incentives the second player to use her 'power of extraction' while the social externality is still available, (ii) yields to more asymmetric profit distributions when subjects win the social externality and (iii) delays the breach period in case of coordination failure. Furthermore, the first choice of the first player is determinant for getting the reward

Mercado televisivo en España: Aproximación microeconómica

El mercado televisivo es uno de los sectores claves de la economía actual por el papel que juega dentro de las sociedades modernas. Dentro de la propia economía, el mercado de la televisión se presenta como un sector complejo que da cabida a grandes grupos de comunicación que son los servidores de dicho mercado. En España, el mercado televisivo se caracteriza por un gran duopolio que ha ido concentrando más cuotas de poder durante los últimos años. Se presentará mediante las herramientas que nos otorga la microeconomía una aproximación al mercado televisivo español para poder estudiarlo, esquematizarlo y modelizarlo. Con ello se introducirá la microeconomía a una realidad y a unos hechos que constituyen el mercado televisivo español; con el fin de que la microeconomía se muestre como una herramienta útil en el abordaje de la economía, en este caso, el mercado televisivo en España