Voting Weights or Agenda Control: Which One Really Matters?

Much of the EU institution literature deals with the distribution of voting power in the Council and European Parliament. The increasingly sophisticated models on EU decision making tend to overlook issues pertaining agenda formation and control in various decision making bodies. This article argues that agenda control is extremely important in all collective decision making bodies. Indeed, agenda control may render the voting power distribution issue largely irrelevant.Agenda control, amendment procedure, no-show paradox, successive procedure

Public Choice and Altruism

The public choice literature has paid little attention to altruism, and the few works that do deal with it usually focus on the tradeoff between selfish and unselfish preferences, assuming some shared set of unselfish preferences. This focus leaves the question open as to whether unselfish but conflicting beliefs can be the source of public choice problems. This paper examines conflicting ethical beliefs among purely altruistic individuals to show that many of the problems that appear to go away if people are altruistic (assuming notions of the public interest are shared) return if notions of the public interest conflict no matter how altruistic people may be.Altruism

Pyramidal Democracy

We consider a decentralized, multilayered representative democracy, where citizens participate in deliberative policy formation after self-organizing into a pyramidal hierarchy of small groups. Each group elects a delegate, who expresses the deliberative consensus of that group at the next tier of the pyramid. The pyramid thus acts as a communications network which efficiently aggregates useful information and policy ideas. It is also a powerful meritocratic device, which channels legislative responsibility towards the most committed and competent citizens. This yields a practical implementation of deliberative democracy in a large polity.deliberative democracy

Judgment Aggregation under Issue Dependencies

We introduce a new family of judgment aggregation rules, called the binomial rules, designed to account for hidden dependencies between some of the issues being judged. To place them within the landscape of judgment aggregation rules, we analyse both their axiomatic properties and their computational complexity, and we show that they contain both the well-known distance-based rule and the basic rule returning the most frequent overall judgment as special cases. To evaluate the performance of our rules empirically, we apply them to a dataset of crowdsourced judgments regarding the quality of hotels extracted from the travel website TripAdvisor. In our experiments we distinguish between the full dataset and a subset of highly polarised judgments, and we develop a new notion of polarisation for profiles of judgments for this purpose, which may also be of independent interest

Direct Democracy Versus Representative Democracy: A Theoretical Approach

Fecha de Lectura de Tesis Doctoral: 12 Diciembre 2019The main purpose of this PhD dissertation is to compare the systems of direct and representative democracy from a theoretical point of view. Faced with the undeniable success and popular acceptance of instruments of direct democracy such as referendums and popular consultations when making decisions, a very natural first question is when voters prefer a system of direct democracy or a system of representative democracy. In Chapter 1, we propose a model to investigate under which conditions voters prefer either one or the other system. We show that direct democracy is the preferred instrument for collective choices in societies in which the populist rhetoric of people against the elite succeeds. We also find that the demand for direct democracy is increasing in the polarization of the electorate. The success of direct democracy is recently resulting in the emergence of social movements and political parties asking for the direct participation of citizens in the decision making process. These groups highlight the inability of representative democracy to implement what the majority of people desires for each issue that comes up for discussion. In Chapter 2, we study under which conditions direct democracy and representative democracy may be equivalent in terms of outcomes. We find that this equivalence becomes less likely to be held the more divided the electorate in evaluating which are the more relevant issues for the society and the less polarized are the politicians. Concerning how voters’ preferences are aggregated, in Chapter 3 we consider a class of preference aggregation mechanisms, known as scoring rules, and show that none of them is guaranteed to select the Condorcet winner from among the set of alternatives at every profile of preferences, except in very specific cases

Majority voting on restricted domains

In judgment aggregation, unlike preference aggregation, not much is known about domain restrictions that guarantee consistent majority outcomes. We introduce several conditions on individual judgments sufficient for consistent majority judgments. Some are based on global orders of propositions or individuals, others on local orders, still others not on orders at all. Some generalize classic social-choice-theoretic domain conditions, others have no counterpart. Our most general condition generalizes Sen's triplewise value-restriction, itself the most general classic condition. We also prove a new characterization theorem: for a large class of domains, if there exists any aggregation function satisfying some democratic conditions, then majority voting is the unique such function. Taken together, our results support the robustness of majority rule

Aggregating sets of judgments: two impossibility results compared

May’s celebrated theorem (1952) shows that, if a group of individuals wants to make a choice between two alternatives (say x and y), then majority voting is the unique decision procedure satisfying a set of attractive minimal conditions. The conditions are (i) universal domain: the decision procedure should produce an outcome (x, y or tie) for any logically possible combination of individual votes for x and y; (ii) anonymity: the collective choice should be invariant under permutations of the individual votes, i.e. all individual votes should have equal weight; (iii) neutrality: if the individual votes for x and y are swapped, then the outcome should be swapped in the same way, i.e. the labels of the alternatives should not matter; (iv) positive responsiveness: supposing all other votes remain the same, if one individual changes his or her vote in favour of a winning alternative, then this alternative should remain the outcome; if there was previously a tie, a change of one individual vote should break the tie in the direction of that change. May’s theorem is often interpreted as a vindication of majoritarian democracy when a collective decision between two alternatives is to be made. Many collective decision problems are, however, more complex. They may not be confined to a binary choice between two alternatives, or between the acceptance or rejection of a single proposition. Suppose there are three or more alternatives (say x, y and z). In that case, it may seem natural to determine an overall collective preference ranking of these alternatives by applying majority voting to each pair of alternatives. But, unfortunately, pairwise majority voting may lead to cyclical collective preferences. Suppose person 1 prefers x to y to z, person 2 prefers y to z to x, and person 3 prefers z to x to y. Then there are majorities of two out of three for x against y, for y against z, and for z against x, a cycle. This is Condorcet's paradox. But a greater number of alternatives is not the only way in which a collective decision problem may deviate from the single binary choice framework of May's theorem. A collective decision problem may also involve simultaneous decisions on the acceptance or rejection of multiple interconnected propositions. For instance, a policy package or a legal decision may consist of multiple propositions which mutually constrain each other. To ensure consistency, the acceptance or rejection of some of these propositions may constrain the acceptance or rejection of others. Once again, a natural suggestion would be to apply majority voting to each proposition separately. As we will see in detail below, however, this method also generates a paradox, sometimes called the 'doctrinal paradox' or 'discursive dilemma': propositionwise majority voting over multiple interconnected propositions may lead to inconsistent collective sets of judgments on these propositions. We have thus identified two dimensions along which a collective decision problem may deviate from the single binary choice framework of May’s theorem: (a) the number of alternatives, and (b) the number of interconnected propositions on which simultaneous decisions are to be made. Deviations along each of these dimensions lead to a breakdown of the attractive properties of majority voting highlighted by May's theorem. Deviations along dimension (a) can generate Condorcet's paradox: pairwise majority voting over multiple alternatives may lead to cyclical collective preferences. And deviations along dimension (b) can generate the 'doctrinal paradox' or 'discursive dilemma': propositionwise majority voting over multiple interconnected propositions may lead to inconsistent collective sets of judgments on these propositions. In each case, we can ask whether the paradox is just an artefact of majority voting in special contrived circumstances, or whether it actually illustrates a more general problem. Arrow's impossibility theorem (1951/1963) famously affirms the latter for dimension (a): Condorcet's paradox brings to the surface a more general impossibility problem of collective decision making between three or more alternatives. But Arrow's theorem does not apply straightforwardly to the case of dimension (b). List and Pettit (2001) have shown that the 'doctrinal paradox' or 'discursive dilemma' also illustrates a more general impossibility problem, this time regarding simultaneous collective decisions on multiple interconnected propositions. The two impossibility theorems are related, but not identical. Arrow's result makes it less surprising to find that an impossibility problem pertains to the latter decision problem too, and yet the two theorems are not trivial corollaries of each other. The aim of this paper is to compare these two impossibility results and to explore their connections and dissimilarities. Sections 2 and 3 briefly introduce, respectively, Arrow's theorem and the new theorem on the aggregation of sets of judgments. Section 4 addresses the question of whether the two generalizations of May's single binary choice framework -- the framework of preferences over three or more options and the framework of sets of judgments over multiple connected propositions -- can somehow be mapped into each other. Reinterpreting preferences as ranking judgments, section 5 derives a simple impossibility theorem on the aggregation of preferences from the theorem on the aggregation of sets of judgments, and compares the result with Arrow's theorem. A formal proof of the result is given in an appendix. Section 6 discusses escape-routes from the two impossibility results, and indicates their parallels. Section 7, finally, explores the role of two crucial conditions underlying the two impossibility theorems -- independence of irrelevant alternatives and systematicity --, and identifies a unifying mechanism generating both impossibility problems

Pyramidal Democracy

We consider a decentralized, multilayered representative democracy, where citizens participate in deliberative policy formation after self-organizing into a pyramidal hierarchy of small groups. Each group elects a delegate, who expresses the deliberative consensus of that group at the next tier of the pyramid. The pyramid thus acts as a communications network which efficiently aggregates useful information and policy ideas. It is also a powerful meritocratic device, which channels legislative responsibility towards the most committed and competent citizens. This yields a practical implementation of deliberative democracy in a large polity