[EM] Plurality == FPTP right?

[Jack Santucci]

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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