[EM] Defeat strength, Winning Votes vs. Margins, what to do with equal-ranks on the ballot?
voting at ukscientists.com
Fri May 24 06:37:47 PDT 2019
On 24/05/2019 12:43, Richard Lung wrote:
> With FAB STV, a blank ballot returned means NOTA (without privileging
> that particular preference perm on the ballot paper) and counts as one
> vote towards a quota for leaving an empty seat. Any partially blank
> vote of preferences also counts to a less extent against a seat being
> filled. This procedure establishes absolute preference for the
> candidates as a whole, not just relative preference between them.
> You would indeed have to tell the voters in advance the consequences
> of their being remiss in filling in all the preferences!
> Richard Lung.
> On 24/05/2019 00:24, Stéphane Rouillon wrote:
>> All criterias (Winning Votes, Margins, Relative Margins) have
>> advantages and are acceptable. The fine choice depends on the
>> interpretation you told voters that would be made of blank ballots.
>> If a blank rank means "all bad", WV is perfect. If it means "all the
>> same" Margin is good, and if it means "I don't know but I trust other
>> voters to express a valid opinion about this option", then RM is
>> perfect. Just tell voters the chosen interpretation of blank tanks in
>> advance so they can fill a sincere ballot...
>> Envoyé de mon iPhone
>> Le 22 mai 2019 à 20:18, robert bristow-johnson
>> <rbj at audioimagination.com <mailto:rbj at audioimagination.com>> a écrit :
>>> i'm posting this to the list. i hope it's okay.
>>> i had been asked:
>>> > This "plausible example" you can think of, why don't you show it
>>> to us?
>>> i'm not as good as you guys in dreaming up the number of ballots
>>> ranked however:
>>> ex. A>B>C>D
>>> but could you have a defeat matrix where
>>> but C>A by a smaller defeat strength than A>B or B>C. But D>A by
>>> an even smaller defeat strength, however D<B and D>C?
>>> i dunno how to dream up ballot combinations to do that.
>>> > Without it all I can say that is that the River winner may or may
>>> not be
>>> > a "better choice" than the
>>> > RP winner.
>>> > River's main practical point is that it easier than Schulze and RP
>>> to use.
>>> i think it's more complicated than RP. it's RP with an additional
>>> i have to say i am still not convinced of WV. probably
>>> Schulze-Margins is still the best, but RP-Margins good enough and
>>> possibly easier to sell to policy makers and the public.
>>> i like Margins in principle: The percentage Margin is
>>> (WV-LV)/(WV+LV) and is a measure of the decisiveness of defeat,
>>> without respect to the size of the election. So 5% defeat is a more
>>> decisive defeat than a 4% defeat.
>>> But if you consider every Condorcet pair as it's own little
>>> election, then the salience of the election would be the number of
>>> voters that weigh in on it, which is WV+LV.
>>> So if the net defeat strength (the index to rank the pairs) is the
>>> product of how important the election is with the decisiveness of
>>> defeat you get:
>>> (WV+LV) x (WV-LV)/(WV+LV) = WV - LV
>>> it just seems to me that Margins is better than WV.
>>> but say, WV, is a good idea for defeat strength. is LV a better idea?
>>> r b-j rbj at audioimagination.com <mailto:rbj at audioimagination.com>
>>> "Imagination is more important than knowledge."
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