But, isn't that the whole point? ... that a compromise, perhaps centrist, candidate can emerge victorious?
Just a friendly note: this visualization means nothing without context, and is far from "obvious". Unfortunately, I'd place this in the category of "things that are obvious to people who already believe it". Is there a better way to go about explaining your idea?
To paraphrase, this is a simulation which places candidates and voters on a two-parameter preference space. This is useful because two dimensions are easy to visualize, but the same intuitions apply to higher-dimensional spaces.
Each point is colored to answer "which candidate wins when the popular opinion is normally distributed about this point?". That means the fractured visualization shows IRV's non-monotonicity, and how even when popular opinion is close to a centrist candidate (here in red) it might be that the voting system results in the election of an extreme candidate (green).
With IRV, though, I could see a situation where they are much more likely to win simply because, nowadays, Republicans' and Democrats' general level of mutual disdain is such that I wouldn't be surprised if it ends up being common for people who identify with one major party to rank the candidate from the other major party below every other candidate more-or-less out of spite.
This is a symptom of our current system. Anybody who has any ambition in politics will modify some of their positions to fit one of the major two parties. If running for another party wasn't a death sentence, you would see more competent candidates in those parties.
Which is worth doing because, regardless of what the ideal situation is, if it's associated with a spectacularly bad outcome in one of the earlier elections that uses it, that's going to be a big impediment to wider adoption.
So the minor parties (and independents) are eliminated first, and their preferences are distributed. Which usually means than one of the major party candidates scrapes over 50%, reflecting the minor party voters' basic preference for one of the major parties over the other.
In this (common) situation, I think IRV actually works really well.
The major parties still end up in government, but they see the first-preference percentages for the minor parties, and understand what policy positions are important to the electorate.
Edit: As much as everyone's trashing IRV as "horrible" I don't see a simple, worrisome case where it violates monotonicity; those seem limited to really pathological electorates where nothing will make them happy anyway.
It's terrible because the loser-elimination step that makes non-monotonicity an issue also makes it less straightforward to tabulate, not because non-monotonicity is an issue outside of edge cases.
Difficulty in tabulation affects speed of, certainty of, and confidence in results, as well as cost of implementation.
> Maybe I react differently from the typical voting system enthusiast?
Nope, especially on neglecting pragmatics like tabulation; that's practically a hallmark of voting system enthusiasts.
Which doesn't rise to the level of "that is so bad it must be stopped".
>> Maybe I react differently from the typical voting system enthusiast?
>Nope,
Kind of strange, since the entire reason for my confusion and joining this thread is because of enthusiasts' doom-and-gloom about the quality of the results themselves, and how they worry about the edge cases and I don't.
Are you invigorated by the cost fears? Because they seem like a sliver compared to the cost of Gore vs Bush.
If I can hurt my preferred candidates chances of winning by ranking them higher on my ballot then the voting system is broken.
Non-monotonicity solely on a few pathological edge cases where voter preferences are a nigh-intransitive clusterf—- is not a problem.
The reason there are not more examples like this one is that most governments don't release enough information about ballots in IRV elections.
But ... is there maybe a truncated explanation of the general dynamic there?
100 - A > C > B
100 - B > C > A
40 - C > A > B
10 - C > B > A
The problem is that the B > C > A don't get their second choice considered. Why does this matter? Look at it when you put the votes into pairs.
A vs B: 140 people think A > B. 110 think B > A.
A vs C: 100 people think A > C. 150 think C > A.
B vs C: 110 people think B > C. 140 think C > B.
The theoretical candidate was everyone's second preference. That sounds like quite a good compromise.
You rank 1) Indian 2) Chinese and 3) Italian
Your partner ranks 1) Gastropub 2) Chinese and 3) Steakhouse
you're going to get Chinese food, not because it exists on a line between each of your first choices, but because it is acceptable to each of you, if not preferred. It is a compromise by definition.
Chinese food isn't a compromise, a blend between Italian, Indian, Gatropub and Steakhouse food.
In Chinese food there isn't a little bit from every other choices. A candidate being chosen on virtue of a compromise by the numbers doesn't mean s/he aggregates some ideas from other candidates.
Hence my remark about that candidate being on a different spectrum from the others.
I am not saying he shouldn't be chosen or that people wouldn't be happy about it, I am saying that his ideas aren't a compromise from the other candidates' ideas.
How many axes can you chart a poltician's positions on?
Authoritarian<>Libertarian
Traditional Values <> Social Relational Values
Survival Values<>Self Expression Values
Interventionalist <> isolationist
That's just a few from https://en.wikipedia.org/wiki/Political_spectrum
Say in the US 2016 election Sanders had run as a 3rd party. He was a liberal populist. He might well have been the second choice of both the Trump and Clinton voters, despite not being positioned between the two. He'd still have been the compromise candidate.
So let's talk 2016 presidential election
I'd imagine that a Trump Voter's ballot would look like the following if Sanders had run as an independent.
1) Trump 2) Sanders 3) Gary Johnson (Maybe with a flip on 2/3)
Clinton voters would be
1) Clinton 2) Sanders
Neither primary choice would be acceptable to the other. There would be some voters who preferred Sanders first.
Since then the second-tier candidates have done what you say about promoting each other: "vote for me and for X". If one loses, the other could win in the next round. IRV has a moderating influence on how candidates campaign. By making a bid for those later rounds viable, now everyone has an incentive to build strong coalitions before they even get into office.
Would another system work better? Maybe, but I still count it as an improvement over FPTP.
Now, arguably this is IRV functioning as designed, where the city's progressive wing could vote as a block without worrying about 2 candidates splitting the vote. It was very much non-intuitive, though, and a lot of London Breed supporters were quite pissed off. IRV allows you to "vote for a position" rather than "vote for a person", but many voters are still stuck in the "but....they got fewer votes!" mindset.
You meant after completing all the rounds of IRV, Mark Leno had more votes despite London Breed having more first place votes.
Which, yeah, is the whole point of IRV (and, with slight variations, most ranked ballots methods): a plurality winner that doesn't have broader support but ends up at the bottom of ballots not ranking them first shouldn't generally win over someone who has broader appeal just because the broad appeal splits first place support with another candidate.
> IRV allows you to "vote for a position" rather than "vote for a person", but many voters are still stuck in the "but....they got fewer votes!" mindset.
No, it lets you vote for a person, and also specify, “if not Alice, then my vote goes to Bob”. The winner in IRV is always the candidate with the most votes at the end of the process; reporting only first place votes as votes for the candidate is just wrong reporting of IRV counts.
Absolutely, it's more complex than a simple majority. But I think "bizarre" is unfair.
In practice, I think it helps to provide a diversity of representatives that more closely reflect the diversity of views in the electorate.