The expected utility of voting
I believe thereâ€™s an extensive, sophisticated social science literature on the expected utility of voting in elections which has made some progress beyond the speculations posted above. Could anyone whoâ€™s up-to-speed post a reference to an accessible summary to save us the trouble of trying to reinvent the wheel?
This brings me to one of those papers I’ve been meaning to write for years (I wrote a several drafts of a joint paper with Geoff Brennan, but we never quite converged), and which has finally (2005!) been written by someone else. The idea was to prove an assertion I’ve made quite a few times in academic papers, and here at CT, that, as long as voters have ‘social’ rather than ‘egoistic’ preferences, the expected utility of voting is independent of the size of the electorate, and potentially large enough to justify high levels of participation. You can read this paper by Edlin, Gelman and Kaplan (PDF file). There’s an excellent appendix on why the probability of a decisive vote is of order 1/n.
There’s still the question of why people vote when one side or the other is bound to win. EGK have a go at this, and in my paper on the subject, I say
This approach, in which b [the social benefit of the preferred party winning] is a simple step- function, may be replaced by a more sophisticated one in which b depends not only on the party elected, but on the size of its majority. This would be consistent with the fact that there is a substantial, though normally reduced, turnouts in elections which are perceived as foregone conclusions.)
That’s not a complete solution, and I think it’s also important to consider that voting per se is considered as a social duty or as yielding social benefits, but I think it’s at least as important as expressive motives.
fn1. Quiggin, J. (1987), Egoistic rationality and public choice: a critical review of theory and evidenceâ€™, Economic Record 63(180), 10â€“21.