[EM] MAS defined
fsimmons at pcc.edu
Fri Oct 7 13:32:18 PDT 2016
So MAS doesn't strictly satisfy the CD criterion, but a simple defensive
measure by the A faction can keep B from winning; they just have to make
sure that B's median score is zero by down voting B on a few ballots.
As Michael pointed out recently, plain Range with high resolution ballots
provides a similar chicken defense for A. But MAS does the same thing with
three slots, so I think it is an improvement.
I agree that ICT is better than MAS, but not for public consumption.
A more succinct (but equivalent) way to define MAS would be "Elect the
candidate with the highest total score among all those tied for highest
Jameson's definition is probably better psychologically.
A grade ballot version would be "Elect the candidate with the highest
average grade among the candidates tied for highest median grade."
Regarding the resolution of blanks on MAS style ballots: Let the candidates
top rated on the ballot decide between down and middle. Assuming the
candidates at least publish an approval ballot before election day, this
adjustment could be automated during the count.
Michael Ossipoff wrote ...
> Yes, if both factions of the majority (A & B) cooperate by bottom voting C,
> but not eachother, then yes, A, the larger faction of the majority, wins.
> But what if B, the other faction of the majority, defects instead of
> They don't rate A or C above bottom.
> Now B is the only candidate not bottom voted by a majority.
> Additionally, B has more points than anyone else.
> B, with fewer voters than A, wins because the A voters cooperated & the B
> voters defected.
> In 3-Slot ICT, if the A voters middle-rate B, & the B voters bottom-vote A
> (both factions bottom voting C), then C wins. The B voters should have
> cooperated to beat C.
> (The C voters bottom-vote A & B).
> Michael Ossipoff
> On Oct 6, 2016 11:41 AM, "Jameson Quinn" <jameson.quinn at gmail.com> wrote:
> > I've been working on a simple three-slot system as a next step after
> > approval. This has gone through various iterations and names: U/P, MUMA,
> > NUMA. The latest, and I hope final, version is MAS, Majority Acceptable
> > Score. Here's an explanation, intended for those without a voting theory
> > background. The basic system is described in 3 sentences in the first
> > paragraph; the second paragraph describes the default rule, which is
> > worthwhile but not absolutely essential to the system; and the next two
> > paragraphs give some scenarios.
> > For each candidate, you may upvote, ?midvote?, or downvote. Candidates
> > with a majority of downvotes are eliminated, unless that eliminates
> > everyone. The remaining candidates get 2 points for every upvote and 1
> > every midvote. Most points wins.
> > When people leave a candidate blank, that could mean one of two things:
> > ?never heard of this person?, which should count as a downvote for
> > or ?no strong feelings?, which should count as a midvote (because if the
> > voter really disliked the candidate they would have downvoted). To
> > distinguish these possibilities, see if the candidate?s score from
> > non-blank votes averages at least half a point per voter; for instance,
> > this would be true if they were upvoted by 25%, or explicitly midvoted by
> > 50%. If the score is this good, that candidate is reasonably well-known
> > well-liked, so blanks count as midvotes; if it isn?t, that candidate is
> > relatively unknown, so blanks count as downvotes.
> > MAS is good at dealing with a vote-splitting situation ("chicken
> > so called because in many voting systems it can work like a game of
> > between the two majority subfactions). Say that one "side" of voters have
> > 55%, but there are two candidates on that side splitting the vote and
> > one on the other side. In this case, assuming voters on either side
> > downvote the candidates on the other side, the 45% candidate will be
> > eliminated by downvotes, and whichever subfaction of the majority has
> > supporters will win.
> > MAS also deals well with a "center squeeze" scenario, in which a centrist
> > candidate faces off against candidates on either side. Assuming all three
> > are equally qualified and likeable, the centrist will probably be able to
> > beat either side in a one-on-one race (because leftist voters will prefer
> > Center over Right, and vice versa); but it is quite possible that there
> > will be more partisans on either side than in the center. In this case,
> > centrist should not be punished simply for being more "crowded"
> > ideologically; their ability to dominate one-on-one means they should
> > But many voting systems, such as IRV, can eliminate the centrist
> > prematurely, giving results like the tragic outcome in Egypt 2012.
> > Meanwhile, other systems, such as Condorcet, can enable tricky strategies
> > by one side to possibly win. In MAS, as long as the center candidate was
> > preferred by a respectable number of voters (say, 20% or more),
> > from voters in either wing would probably be enough to let the centrist
> > win; and *either* defensive "midvoting" from the weaker wing or defensive
> > "downvoting" by the centrists would probably be enough to stop a takeover
> > by the stronger wing.
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