Measuring polarization in preferences

In this paper, we study the measurement of polarization in collective decision making problems with ordinal preferences over alternatives. We argue that polarization can be measured as an aggregation of antagonisms over pairs of alternatives in the society. We propose a measure of this sort and show that it is the only measure satisfying some normatively appealing conditions. ∗Department of Economics, School of Business and Economics, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands; E-mail: [email protected]. This research was partially financed by the Netherlands Organisation for Scientific Research (NWO) with project nr. 400-09-354. †Department of Economics, Istanbul Bilgi University, Istanbul, Turkey and Departement d’Economie, Ecole Polytechnique 91128 Palaiseau, France, E-mail: [email protected]. Most of this work has been accomplished when Ozkes was visiting Maastricht University in July 2013. This visit has been partially supported by COST Action IC1205 on Computational Social Choice. ‡Department of Quantitative Economics, Maastricht University, P.O. Box 616, 6200 MD Maastricht, the Netherlands; E-mail: [email protected]