An experimental study of the efficiency of unanimity rule and majority rule (original) (raw)
Related papers
2017
We develop a simple model that rationalizes why less stringent majority rules are preferable to unanimity in large committees. Proposals are randomly generated and the running proposal is adopted whenever it is approved by a sufficiently large share of voters. Unanimity induces excessive delays while too weak majority requirements induce the adoption of suboptimal proposals. The optimal majority rule balances these two inefficiencies: it requires the approval by a share equal to the probability (assumed to be constant across proposals) that a given member gets more than the average welfare associated with the running proposal. Various extensions are considered.
In search of optimum ?relative unanimity?
Public Choice, 1983
In their classic work, The Calculus of Consent, deal with a number of critical public choice issues. One of the most basic of these issues is whether the decision-time costs associated with a rule of full unanimity are sufficiently high as to mandate the adoption of a 'relative unanimity' rule (/~ la Wicksell, 1896).
Journal of Theoretical Politics, 2010
Little attention has been paid to the differences between absolute majority rule and simple majority rule, which differ in their treatment of absences and ‘votes to abstain’. This article fills that gap by undertaking a probabilistic analysis of the two voting rules assuming two alternatives and a quorum requirement for simple majority rule. The rules are compared in both a modified sincere setting and a strategic setting using five criteria: (1) the Pareto criterion, (2) the BT criterion (Buchanan and Tullock, 1962), (3) the Expected Social Gain criterion, (4) the Responsiveness criterion, and (5) a modified version of Rae’s criterion. In the sincere setting, we find that simple majority rule (with and without a quorum) outperforms absolute majority rule under most conditions for four out of the five criteria. In the strategic setting, we find that the voting rules perform much more similarly.
Ordering Pareto-optima through majority voting
Mathematical Social Sciences, 2001
A commodity is shared between some individuals: There is an initial allocation; some selection procedures are used to choose an alternative allocation and; individuals decide between keeping the initial allocation or shifting to the alternative allocation. The selection procedures are supposed to involve an element of randomness in order to re°ect uncertainty about economic, social and political processes. It is shown that for every allocation,¸, there exists a number, ³(¸) 2 [0; 1], such that, if the number of individuals tends to in¯nity, then the probability that a proportion of the population smaller (resp. larger) than ³(¸) prefers an allocation chosen by the selection procedure converges to 1 (resp. 0). The index ³(¸) yields a complete order in the set of Pareto optimal allocations. Illustrations and interpretations of the selection procedures are provided. ¤ We are grateful to Edi Karni and Herv ¶ e Moulin for valuable discussions and helpful comments.
Ameliorating Majority Decisiveness through Expression of Preference Intensity
American Political Science Review, 2002
In pairwise voting, when a simple majority rule produces a winner, that winner is robust to the minority's preferences. The typical means of protecting the minority from the decisiveness of the majority is by increasing the required majority or by augmenting the simple majority rule with constitutional constraints. In the former case the required majority q becomes larger than one-half, and this implies that the q-majority rule becomes biased in favor of one of the alternatives, usually the status quo. In the latter case the augmented rule becomes biased in favor of the minority. The main issue examined in this paper is whether the amelioration of majority decisiveness can be attained by unbiased voting rules that allow some restricted expression of preference intensities. Our results clarify that the use of scoring rules provides a positive answer to the above question when voters resort to variable degrees of coordinated strategic voting. The results are illustrated in the spe...
Efficiency in the Degree of Compromise: A New Axiom for Social Choice
Group Decision and Negotiation, 2000
We introduce a social choice axiom called "efficiency in the degree of compromise". Our axiom is based on the trade-off between the quantity and quality of support that an alternative receives. What we mean by the quantity of support is the number of voters behind an alternative, while the quality of support is about the definition of "being behind" depending on the rank of an alternative in voters' preference orderings. Naturally, one can increase the quantity of support of an alternative to the expense of giving up from its quality. We say that an alternative is an "efficient compromise" if there exists no other alternative with an at least equal quantity of support with a higher quality. Our efficient compromise axiom is based on not choosing inefficient compromises. We introduce it and show that many standard social choice rules of the literature, such as Condorcet-consistent rules, plurality with a runoff, the Borda count and the single transferable vote, may choose inefficient compromises.
A methodological note on a weighted voting experiment
Social Choice and Welfare, 2014
We conducted a sensitivity analysis of the results of weighted voting experiments by varying two features of the experimental protocol by Montero et al. (2008): (1) the way in which the roles of subjects are reassigned in each round (random role, RR, versus fixed role, FR) and (2) the number of proposals that subjects can simultaneously approve (multiple approval, MA, versus single approval, SA). It was observed that the differences in these protocols had impacts on the relative frequencies of minimum winning coalitions as well as how negotiations proceed. Our analysis favors a protocol with FR-SA for future research, because this protocol induces subjects to commit fewer errors in their decision making than the protocol with RR-MA, and because proposal-objection dynamics are more frequently observed under FR-SA than under RR-MA.