[EM] MTA vs. MCA (was "An ABE solution")

[Jameson Quinn]

Why ranked and not graded ballots? This method would be consistent with
non-normalized ballots (with no top-ratings or no bottom-ratings) being
strategically optimal in some cases, arguably in most real-world cases. As
Balinski and Laraki argue, using commonly-understood ratings/grades is the
only way to avoid having strategy be, not just a consideration in rating,
but the only logically coherent one. And it's easier, cognitively, to
separately rate each candidate on a meaningful scale than to sort them into
a rank order.

Jameson

2011/11/20 C.Benham <cbenhamau at yahoo.com.au>

>
> Forest Simmons wrote (17 Nov 2011):
>
> MTA vs. MCA
>
> I like MTA better than MCA because in the case where they differ (two or
> more
> candidates with majorities of top preferences) the MCA decision is made
> only by
> the voters whose ballots already had the effect of getting the ”finalists”
> into
> the final round, while the MTA decision reaches for broader support.
> Because of this, in MTA there is less incentive to top rate a lesser evil.
> If
> you don’t believe the fake polls about how hot the lesser evil is, you can
> take
> a wait and see attitude by voting her in the middle slot. If it turns out
> that
> she did end up as a finalist (against the greater evil) then your ballot
> will
> give her full support in the final round.
>
> <end Forest quote>
>
> I buy this. I agree that MTA is a bit better than MCA. Well done Mike.
>
> * Voters submit 3-slot ratings ballots, default rating is Bottom
> signifying least
> preferred and not approved. Top-rating signifies most preferred and
> approved.
> Middle-rating also signifies approval.
>
> If any candidates are Top-rated on more than half the ballots, elect the
> one of
> these with the most approval.
>
> Otherwise elect the most approved candidate.*
>
> A slight marketing problem could be that the difference between this and
> MCA
> (and also between those and a third possible similar method: the TR winner
> wins if
> s/he has majority approval, otherwise the most approved candidate wins)
> could
> to some members of the public appear to be quite arbitrary and unimportant.
>
> Also of course MTA is little bit more complex to count than MCA. But on
> the positive
> side, it has just occurred to me that it would work better than MCA
> extended to using
> 4-slot ballots (with as with 3 slots, any rating above the bottom-most
> slot is interpreted
> as approval).
>
> I suppose by the same reasoning we could improve ER-Bucklin(whole), which
> has
> been given the briefer and quite apt new name by Mike O. of "ABucklin".
>
> My stab at defining the so improved version:
>
> *Voters submit ranking ballots, equal-ranking and truncation allowed.
> Ranked (i.e.not
> truncated) candidates are considered to be approved.
>
> Rankings are interpreted as ratings thus: candidates ranked below no
> others are in the top
> ratings slot. Those with x candidates ranked above them are in (x-1)th.
> ratings slot from
> the top. (So A=B>D is interpreted as A and B in top slot, second-highest
> slot empty,
> D in third-highest slot).
>
> Say the ratings slots are labelled from highest (signifying most
> preferred) down as alphabetical
> grades A, B, C, D etc.
>
> If any candidates are graded A on more than half the ballots then elect
> the most approved one
> of these.
>
> Otherwise if any candidates are graded A or B on more than half the
> ballots then elect the most
> approved one of these.
>
> Otherwise if any candidates are graded A or B or C on more than half the
> ballots then elect the
> most approved one of these.
>
> Continue in this vein considering the next lowest grade each round until
> there is a winner, or if
> that fails then elect the most approved candidate.*
>
> I think IBIFA is still quite a lot better than any of these methods, but
> it is more complicated.
> IBIFA has a less strong truncation incentive and the IBIFA winner will
> never be pairwise-beaten
> by the winner of any of these methods.
>
> Chris Benham
>
>
>
>
>
>
>
>
> ----
> Election-Methods mailing list - see http://electorama.com/em for list info
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.electorama.com/pipermail/election-methods-electorama.com/attachments/20111121/ca059d88/attachment-0004.htm>