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

[fsimmons at pcc.edu]

Chris,

I like this generalization!

Forest

----- Original Message -----
From: "C.Benham" 
Date: Sunday, November 20, 2011 8:04 am
Subject: MTA vs. MCA (was "An ABE solution")
To: em , Forest W Simmons , MIKE OSSIPOFF , "Dr Douglas R. Woodall" 

> 
> 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.
> 
> 
> 
> 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
> 
> 
> 
> 
> 
> 
> 
> 
>