Generalized multi-peaked model of electoral preferences

Social choice;Group choice;Condorcet paradox;aggregation of preferences

Popova, Anna

关键词: Social choice;    Group choice;    Condorcet paradox;    aggregation of preferences;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/50344/Anna_Popova.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Individuals often need to make decisions as a group on di erent levels, ranging from a family unit, to professional organizations, to larger political and economic units. Societies choose their leaders, while companiesgain business insights and develop marketing strategies using aggregation methods. These decisions arehighly resource-intensive and have important implications for the quality of life, safety, and self-expression in public life. Therefore, it is extremely important to aggregate individual preferences correctly.The area of theoretical Social Choice provides us with bearish answers that a consensus may be unobtainable and that any group choice may be impugnable. Even worse, the choice of the best option may depend on the choice of the aggregation procedure. Nevertheless, the analysis of real-world data routinelyargues against these theoretical predictions: the outcomes of aggregation procedures in real-world data setsagree remarkably well. This contradiction has puzzled researchers for decades. To solve this puzzle I proposea Generalized Multi-peaked model of preferences.The Multi-peaked model is consistent with the predictions from the theoretical literature on Social Choiceand with the novel empirical evidence. I model the structure of group preferences by assuming that,first, people share a limited number of points of view and, therefore, form subgroups on the basis of similar preferences. Thus, the distribution of preferences of the group is a mixture of the preferences of these subgroups. Second, within a group, people deviate slightly from a typical point of view and thereby providea variety of opinions.I capture these two assumptions by introducing modes, i.e., true/typical points of view of a group, and Kernel functions, i.e., deviations from the modes, into the model. I show that Kernel functions bear all the responsibility for the high rates of consistency among aggregation methods, as well as the rarity of cyclical social preferences in real-world data.