What should the main objectives of voting method advocates be, and what are the important and interesting questions?
For single-winner elections, I believe the most important objective is switching away from plurality. The most interesting problem is deciding which of the alternatives to plurality we should switch to. Approval, score, STAR, instant runoff voting (single-winner RCV), and Condorcet methods all have their pros and cons, and it’s fascinating to delve into them. But the real standout method is plurality, and it stands out by being terrible. Aside from simplicity, these other methods beat plurality in every way (and approval voting is every bit as simple). STAR is my favorite voting method, but if I were using an approval ballot to vote on which voting method we should use I’d vote for everything except plurality.
For multi-winner elections, and single-winner elections that could be converted into multi-winner election (e.g. for Congress), the most important objective is getting proportional representation. Again, the choice of which voting method to use for it is extremely interesting, but getting proportional representation at all is the main thing.
There are many criteria on which to evaluate voting methods. Some of the main ones:
- Utilitarian efficiency (as is measured by Voter Satisfaction Efficiency, for example)
- Expressiveness, i.e. how well can voters convey they opinions on their ballots
- How difficult it is for ordinary voters to understand
- How well it can handle large numbers of candidates on the ballot
- Cost of implementation
- How much more influence strategically savvy voters have over the outcome that strategically naïve voters
- How often voters are incentivized to vote dishonestly (e.g. voting for a viable Republican over a preferred Libertarian in a plurality contest)
- Whether everything goes to hell if a lot of people vote strategically
- Third party visibility
- Which groups politicians are incentivized to appeal to
- Whether there’s a pro-extremist bias
The obvious point is worth emphasizing: no one voting method is best across every criterion. For example, I believe my favorite single-winner method, STAR, is worse than approval on simplicity, cost of implementation, and honesty, and worse than IRV in terms of how much more influence strategic voters wield than naïve voters there there’s a small number of candidates. Different people and different communities who value different criteria can have well-justified differing preferences between voting methods as a result. If one city wants a voting method that simple and cheap to implement, another one wants a voting method with as few strategic considerations as possible, and a third wants a voting method that reliably picks the best candidate out of a field of twenty, those cities may want to go for approval, IRV, and STAR, respectively. That said, it is very much possible to prefer a voting method for the wrong reasons, like when a third party endorses IRV because they think it’s the best for helping them grow (it’s not) or because it’s the only one they’ve heard of.
Ultimately, I prefer discussing the pros and cons of different methods over advocating for one specific voting method. These differences are significant and extremely interesting, but the most important objectives are getting proportional representation and getting rid of plurality.