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Group identification with (incomplete) preferences
Author(s) -
Cho Wonki Jo,
Saporiti Alejandro
Publication year - 2020
Publication title -
journal of public economic theory
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 32
eISSN - 1467-9779
pISSN - 1097-3923
DOI - 10.1111/jpet.12387
Subject(s) - mathematical economics , identification (biology) , voting , value (mathematics) , group (periodic table) , majority rule , degeneracy (biology) , class (philosophy) , corollary , degenerate energy levels , microeconomics , economics , mathematics , computer science , combinatorics , law , political science , statistics , bioinformatics , botany , chemistry , physics , organic chemistry , quantum mechanics , artificial intelligence , politics , biology
We consider the problem of identifying members of a group based on individual opinions. Since agents do not have preferences in the model, properties of rules that concern preferences (e.g., strategy‐proofness and efficiency) have not been studied in the literature. We fill this gap by working with a class of incomplete preferences derived directly from opinions. Our main result characterizes a new family of group identification rules, called voting‐by‐equitable‐committees rules , using two well‐known properties: strategy‐proofness and equal treatment of equals. Our family contains as a special case the consent rules (Samet & Schmeidler. J. Econ. Theory, 110 (2003), pp. 213–233), which are symmetric and embody various degrees of liberalism and democracy; and it also includes dictatorial and oligarchic rules that value agents’ opinions differently. In the presence of strategy‐proofness, efficiency turns out to be equivalent to non‐degeneracy (i.e., any agent may potentially be included or excluded from the group). This implies that a rule satisfies strategy‐proofness, efficiency, and equal treatment of equals if, and only if, it is a non‐degenerate voting‐by‐equitable‐committees rule.