Voter Turnout and Preference Aggregation

We study how voter turnout affects the aggregation of preferences in elections. Under voluntary voting, election outcomes disproportionately aggregate the preferences of voters with low voting cost and high preference intensity. We show identification of the correlation structure among preferences, costs, and perceptions of voting efficacy, and explore how the correlation affects preference aggregation. Using 2004 US presidential election data, we find that young, low-income, less-educated, and minority voters are underrepresented. All of these groups tend to prefer Democrats, except for the less educated. Democrats would have won the majority of the electoral votes if all eligible voters had turned out. (JEL D12, D72)

Aggregation of preferences in attitude scales

The problem of decision-making when evaluating alternatives according to several quality criteria is considered. Information is used about the pairwise comparison of alternatives by criteria: how many times one alternative is preferable to the other. The criteria may have nonuniform scales. The method to form preferences matrices for representing numerical estimates of alternatives in attitude scales is proposed. The properties of the constructed relation are investigated. The algorithms for constructing the relation with the minimum distance from the preferences by criteria are developed. An algorithm for constructing an aggregated relation based on the summation of preferences by criteria is developed. Aggregate relation depends on the method of specifying the distance between the matrices of preferences. The proposed algorithms for constructing an aggregated relation can use coefficients of importance of criteria. The method can be applied in collective choice problems when assigning estimates to alternatives by experts. A comparison of the proposed algorithms with each other and with known decision-making methods is carried out. The software system of multi-criteria choice is developed. The task of choosing start-up projects for the purpose of investing by a venture fund has been solved.

Designing Committees for Mitigating Biases

It is widely observed that individuals prefer to interact with others who are more similar to them (this phenomenon is termed homophily). This similarity manifests itself in various ways such as beliefs, values and education. Thus, it should not come as a surprise that when people make hiring choices, for example, their similarity to the candidate plays a role in their choice. In this paper, we suggest that putting the decision in the hands of a committee instead of a single person can reduce this bias. We study a novel model of voting in which a committee of experts is constructed to reduce the biases of its members. We first present voting rules that optimally reduce the biases of a given committee. Our main results include the design of committees, for several settings, that are able to reach a nearly optimal (unbiased) choice. We also provide a thorough analysis of the trade-offs between the committee size and the obtained error. Our model is inherently different from the well-studied models of voting that focus on aggregation of preferences or on aggregation of information due to the introduction of similarity biases.

Aggregating Incomplete Pairwise Preferences by Weight

We develop a model for the aggregation of preferences that do not need to be either complete or transitive. Our focus is on the normative characterisation of aggregation rules under which each agent has a weight that depends only on the size of her ballot, i.e., on the number of pairs of alternatives for which she chooses to report a relative ranking. We show that for rules that satisfy a restricted form of majoritarianism these weights in fact must be constant, while for rules that are invariant under agents with compatible preferences forming pre-election pacts it must be the case that an agent's weight is inversely proportional to the size of her ballot.

On a Theorem due to Alan D. Taylor about Aggregation of Preferences

In this paper, we show that there does not exist any triple acyclic preference aggregation rule that satisfies Majority property, weak Pareto criterion and a version of a property due to Alan Taylor. We also show that there are non-dictatorial preference aggregation rules and in particular non-dictatorial social welfare functions which satisfy the weak Pareto criterion and Taylor’s Independence of Irrelevant Alternatives. Further, we are able to obtain analogous results for preference aggregation functionals by suitably adjusting the desired properties to fit into a framework which uses individual utility functions rather than individual preference orderings. Our final result is a modest generalisation of Sen’s version of Arrow’s impossibility theorem which is shown to hold under our mild domain restriction. JEL: D71