Equilibria and group welfare in vote trading systems
研究了选民在低信息环境下进行选票交易的博弈，发现交易通常损害群体整体福利，但存在例外，并利用真实数据模拟了委员会中的选票交易均衡与福利变化。
Abstract We introduce a new framework to study the group dynamics and game-theoretic considerations when voters are allowed to trade votes. This model advances prior work by considering vote-for-vote trades in a low-information environment where voters do not know the preferences of their trading partners and do not abstain from voting. All voters draw their preference intensities on two issues from a common probability distribution and then consider offering to trade with an anonymous partner. The result is a strategic game between two voters that can be studied analytically. We compute the Nash equilibria for this game and derive several interesting results involving symmetry, group heterogeneity, and more. This framework allows us to determine that trades are typically detrimental to the welfare of the group as a whole, but there are exceptions. We also expand our model to allow all voters to trade votes and derive approximate results for this more general scenario. Finally, we emulate vote trading in real groups by forming simulated committees using real voter preference intensity data and computing the resulting equilibria and associated welfare gains or losses.