[EM] Plurality == FPTP right?

[Closed Limelike Curves]

Ahh, got it, that makes much more sense. I was confused since it seemed
like using the term "plurality" seemed like it would describe all voting
rules—after all, it's not like we're going to elect the candidate with the
second-best score. But you might if you have a multi-winner election!

On Mon, May 13, 2024 at 2:21 PM Jack Santucci <jms346 at georgetown.edu> wrote:

> Perhaps? I don't know that article very well, but I am broadly familiar
> with how the ideas evolved into the 2007 piece on the 'Burr dilemma.'
>
> For me, "plurality" means "the most votes" -- or, in a district of *M* seats
> it means "the *M* highest vote totals."
>
>
> On Mon, May 13, 2024 at 4:22 PM Closed Limelike Curves <
> closed.limelike.curves at gmail.com> wrote:
>
>> OK, I think I understand now; are you taking the term "plurality" to mean
>> the social choice function still returns a winner, even if that winner
>> doesn't have a score higher than 50%, similarly to how Nagel uses it here
>> <https://www.cambridge.org/core/journals/american-political-science-review/article/abs/effect-of-approval-balloting-on-strategic-voting-under-alternative-decision-rules/35809BC96CFA0DC2B50E1550A190D2BF>?
>> I suppose that makes sense, although it feels a bit surprising. Is that a
>> mathematically meaningful definition? Couldn't I define the social welfare
>> function for FPTP as (1 + fptp_vote_share) / 2 to guarantee a winner always
>> has a "majority" without changing anything meaningful about the method?
>>
>> On Mon, May 6, 2024 at 12:39 PM Jack Santucci <jms346 at georgetown.edu>
>> wrote:
>>
>>> Political scientist here. Please don't pelt me with rotten fruit.
>>>
>>> We generally use three categories to differentiate electoral systems.
>>> The number of categories depends on who's writing, but everyone pretty much
>>> agrees on three: district magnitude (1 in your case), ballot type
>>> (categorical in your case), and then allocation rule (plurality in your
>>> case).
>>>
>>> Shugart, Latner, and I argued here
>>> <https://protectdemocracy.org/work/toward-a-different-kind-of-party-government/>
>>>  that 'FPFP' did not really exist in the US due to the widespread use
>>> of primaries, some of which have been replaced with nonpartisan winnowing
>>> rounds (AK, CA, etc). FWIW, Burnett and Kogan (2015) noted
>>> <https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2519723> this
>>> elision in their conclusion nearly a decade ago.
>>>
>>> Other examples of plurality allocation with categorical ballots *and
>>> multi-seat districts*:
>>> - multiple non-transferable vote (incl. as limited voting)
>>> - single non-transferable vote (incl. as limited voting)
>>> - cumulative voting
>>> - etc...
>>>
>>> I generally stay quiet, but this issue is fundamental enough, I think,
>>> to merit the above contribution. FPTP often comes across as an imaginary
>>> target.
>>>
>>> A purist might insist on calling IRV 'plurality' as well, so long as it
>>> does not require the voter to rank all choices.
>>>
>>> Jack
>>>
>>>
>>> On Mon, May 6, 2024 at 3:10 PM Closed Limelike Curves <
>>> closed.limelike.curves at gmail.com> wrote:
>>>
>>>> I just need to double-check I haven't gone completely insane and both
>>>> of these terms really are synonyms. Comments on the talk page would be
>>>> helpful:
>>>> https://en.wikipedia.org/wiki/Talk:Plurality_voting#Merge_from_FPTP
>>>> ----
>>>> Election-Methods mailing list - see https://electorama.com/em for list
>>>> info
>>>>
>>>
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