Why Voting Fails With More Than Two Choices

[Towlie]

Imagine a poll asking "Which of these is your favorite color?" The choices are Azure, Sky Blue, and Red.

Result:

Azure: 30%
Sky Blue: 30%
Red: 40%

Red is the most liked choice.

Then the same people are polled with the question, "Which of these do you dislike the most?"

Result:

Azure: 20%
Sky Blue: 20%
Red: 60%

Conclusion: The most liked choice is the most disliked choice.

[TygrBright]

1. Santa Fe initiated ranked-choice voting in municipal elections this year.

It was a great success.

oppositionally,
Bright

[unblock]

2. there's no perfect voting system (cf. arrow's impossibility theorem) but the one we have sucks.

my personal favorite as an improvement (recognizing that it's also imperfect) is to have everyone rank all the choices (or at least as many as they care to).

when counting the votes, first eliminate the candidate with the fewest votes looking only at voter's top choice.
then reallocate votes and recount, always counting only each voter's top choices from among the remaining candidates.
repeat the process until everyone has been eliminated except one candidate, deemed the winner.

one huge advantage is that this lets people vote first for their ideal candidate even if they're non-viable, without losing any voting power. e.g., someone could vote for the green party candidate first, and the democratic candidate second. this lets them express their views without given any help to the republican in the process.


this is imperfect as well, because an extremely popular compromise candidate might be everyone's second choice, but no one's number one choice, and get eliminated on the first round. in practice this seems less likely than the problems we currently face....

[Locutusofborg]

3. I guess just about every parliamentary system on the planet

Is a failure then?

[KitSileya]

4. No, but in first past the post elections for unique positions, you only have two choices

If your choice is in third place, (least likely to win) you do better to pick the best of the two most likely to win, otherwise you increase the chance your least liked third choice wins. The US Presidential election is one such instance.

Many parliaments in the world do not have first-past-the-post elections, but rather a variant of proportional representations. Others have FPTP systems, but elect the head of goverment from among those in parliament rather than in a separate, country-wide election.