Implicit utilitarian voting (IUV) is a
voting system
An electoral system or voting system is a set of rules that determine how elections and referendums are conducted and how their results are determined. Electoral systems are used in politics to elect governments, while non-political elections m ...
in which the agents express their preferences by ranking the alternatives (like in
ranked voting
The term ranked voting (also known as preferential voting or ranked choice voting) refers to any voting system in which voters rank their candidates (or options) in a sequence of first or second (or third, etc.) on their respective ballots. Ra ...
), and the system tries to select an alternative which maximizes the sum of utilities, as in the
utilitarian social choice rule
In social choice and operations research, the utilitarian rule (also called the max-sum rule) is a rule saying that, among all possible alternatives, society should pick the alternative which maximizes the ''sum of the utilities'' of all individual ...
and
utilitarian voting.
The main challenge in IUV is that the rankings do not contain sufficient information to calculate the utilities. For example, if Alice ranks option 1 above option 2, we do not know whether Alice's utility from option 1 is much higher than from option 2, or only slightly higher. So if Bob ranks option 2 above option 1, we cannot know which of the two options maximizes the sum of utilities.
Since a voting-rule that can only access the rankings cannot find the max-sum alternative in all cases, IUV aims to find a voting-rule that approximates the max-sum alternative. The quality of an approximation can be measured in several ways.
# The ''distortion'' of a voting-rule is the worst-case (over utility functions consistent with the reported profile of rankings) ''ratio'' between the maximum utility-sum and the utility-sum of the alternative selected by the rule.
# The ''regret'' of a voting-rule is the worst-case (over utility functions consistent with the reported profile of rankings) ''difference'' between the maximum utility-sum and the utility-sum of the alternative selected by the rule.
Some achievements in the theory of IUV are:
* Analyzing the distortion of various existing voting rules;
* Designing voting rules that minimize the distortion in single-winner elections and in multi-winner elections;
* Analyzing the distortion of various ''input formats'' for
Preference elicitation in
participatory budgeting
Participatory budgeting (PB) is a type of citizen sourcing in which ordinary people decide how to allocate part of a municipal or public budget through a process of democratic deliberation and decision-making. Participatory budgeting allows ...
.
Implementation
Implicit utilitarian voting rules are used in th
RoboVotewebsite.
See also
*
Utilitarian cake-cutting Utilitarian cake-cutting (also called maxsum cake-cutting) is a rule for dividing a heterogeneous resource, such as a cake or a land-estate, among several partners with different cardinal utility functions, such that the ''sum'' of the utilities of ...
- the utilitarian principle in a different context.
References
{{Reflist
Social choice theory
Preferential electoral systems
Cardinal electoral systems
Utilitarianism