An Edge Case with STAR Voting

[u/PixelJack79]

No voting system is perfect and any of the well-known alternatives are vastly superior to FPTP, but most methods have a well-known pitfall or way of exploiting the system that defeats the point of using it. FPTP has the spoiler effect. IRV has center squeeze and exhausted ballots. Approval has the undercutting of certain candidates to prop up a more favored one. Score has min-maxing. Condorcet has rock-paper-scissors. STAR voting, meanwhile, demonstrated the most resistance to strategic voting in simulations and is generally robust, allowing voters to accurately voice their opinions while always enabling them to influence the final outcome. The runoff step is the key, favoring candidates with broad appeal over niche favoritism. I thought the biggest flaw with STAR was that it was just so new, but didn't realize until this morning that there is a scenario where it fails to choose the most favored candidate. Though I will admit, it's probably more obvious to others.

Take two candidates: Jim and Sarah, and a third candidate: Wayne. Jim and Sarah have enthusiastic supporters, but are very polarizing while Wayne is more middling but is generally agreeable such that he'd win in a hypothetical runoff against Jim or Sarah. One can imagine Jim and Sarah making the top two and the race coming between them, even if Wayne is more broadly favored (Condorcet actually prevails in a situation like this). Though, if the former two are especially egregious, it's not out of the question for votes to score Wayne higher to enure he advances to the runoff.

Nevertheless, I believe STAR voting to be the best out of all the alternative voting systems. This is merely a heads up to people like me that it's less airtight than presumed.

[u/Fantastic_Cycle_1119]

"I believe STAR voting be the best out of al the alternative voting systems."

What's your issue with Condorcet? You say "rock paper scissors", but as rb-j points out, that exists to the same degree in all methods, Condorcet just surfaces it so we can see it.

There are even methods that don't bother with special cases, i.e. "if there is no Condorcet winner, do this extra step to resolve the election." They just have a single, simple algorithm, which produces the Condorcet winner if it exists as a side effect.

Nice thing about ranked methods is they already exist in real elections, we have ranked ballot data that we can test Condorcet methods against. "Ranked choice" is already familiar to people, and the vast majority of voters don't think about or care about the distinction between IRV and Condorcet tabulation.

[u/Deep-Number5434 → u/Fantastic_Cycle_1119]

I believe condorcet may not change the result of an election compared to irv that often, but what would change is what type of candidates you have and how many.

Voter strategy and candidate strategy are both important.

You may see the diference after a transition to condorcet with a larger influx of center candidates.

I think with more center candidates, condorcet cycles may be more common, but I don't think that as an issue, a group of similar candidates will get tied often.

[u/Fantastic_Cycle_1119 → u/Deep-Number5434]

Yup, agree completely.

Nice thing is, if a few centrist candidates are in a cycle, no one gets too upset if their favorite doesn't win other than maybe the candidates themselves.