CeDEx workshop - John Morgan (UC, Berkeley)

Voluntary Voting: Costs and Benefits

Voting is perhaps the most common mechanism by which societies make collective choices, yet the welfare properties of voting outcomes are often poorly understood. Canonical voting models assume that all eligible voters turn up at the polls, an assumption increasingly at odds with reality. In this lecture, I describe my research on models accounting for the fact that voters face two choices--both whether and for whom to vote. When the decision to vote is modeled as a choice, a new welfare result emerges--equilibrium majority rule voting robustly produces the utilitarian outcome in large elections. Moreover, it is the only voting rule with this characteristic--supermajority rules protect the status quo at a welfare weight equivalent to the square of their proportion. Thus, a 2/3 supermajority role effectively gives 4 times the welfare weight to the status quo. A simple, but powerful intuition about the link between the benefits of voting and expected vote share explains these findings.