[EM] Plurality == FPTP right?

[Closed Limelike Curves]

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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