An Empirical Study of Voting Rules and Manipulation with Large Datasets

Saturday, 15 February 2014
Grand Ballroom B (Hyatt Regency Chicago)
James I. Forshee , Epic Systems Corporation, Verona, WI
The study of voting systems often takes place in the theoretical domain due to a lack of large samples of sincere, strictly ordered voting data. We derive several million elections (more than all the existing studies combined) from a publicly available data, the Net´flix Prize dataset. The Net´flix data is derived from millions of Net´flix users, who have an incentive to report sincere preferences, unlike random survey-takers. Using these elections, we investigate theoretically-possible phenomena, including different voting rules yielding different winners, and the possibility of irrational aggregated preferences. We investigate the occurrence of statistical patterns of interest, such as single- peakedness. In addition, we look at the practical manipulability of elections according to several recently-proposed manipulation algorithms. [This talk includes research developed jointly with Nicholas Mattei and James Forshee.]