Here we get led down a path of rejecting methods for being worse than
plurality in some way, without considering whether they may be better
in other important ways.
Agreed that Approval is better - and very little different.
Asset deserves a bit of study - the candidate you vote for can be part
of deciding who gets elected - sorting this out makes it more complex
than plurality for me.
IRV sounds great to many for what it offers voters - vote for more
than one as in Approval, but rank them to indicate which you like best.
What it tells the vote counters sounds good until you look
close: Look only at what each voter ranks highest; if this identifies
a winner - fine; if not, discard the least liked of what was looked at
but failed to win and try again. Usually this will discard losers and
expose a deserving winner. But sometimes what I describe next happens
to one the voters really liked:
50 A
51 B>A
52 C>A
53 D>A
Counting: 50A; 51B; now 51A; now 53D beats 52C.
Condorcet looks much like IRV to the voters. Counters, looking at all
the ballots above say, will see 153A beating 53D.
On Jun 2, 2011, at 3:14 PM, [email protected] wrote:
There are only two single winner methods that are uniformly better
than Plurality, i.e. that are better in
some ways and worse in none. These two methods make use of
Plurality style ballots, and those voters
who want to use Plurality strategy (marking only their preferred of
the two frontrunners) can do so without
incurring a worse result than they would get in a Plurality election.
The two methods are Approval and Asset. My remarks in the first
paragraph explain why neither of
these methods is in any way worse than Plurality. To see that they
are in some cases better, consider
the following points:
In the case of Approval, if many voter s also mark the candidates
they prefer over their Plurality choice,
the results will often be improved.
In the Asset voting case, consider that when you trust your Favorite
candidate’s ranking of the other
candidates, you can mark you favorite and not worry about Plurality
strategy. It appears that between
eighty and ninety percent of the voters would rather have their
favorite do the ranking. Where do we get
that figure? We get it from Australia where the vast majority of
voters just copy their candidate cards
onto the ballot.
The Aussies are required to rank every candidate - a chore few want to
do for themselves. If voting for as many as in Approval the American
voter should see little pain in ranking these few that they approve of.
In summary, we have shown that both of these methods are at least as
simple and have at least as good
results as Plurality by treating the ballots as Plurality ballots,
and that obviously safe and beneficial
departures from Plurality strategy yield significant improvements in
both cases. Therefore, these two
methods are uniformly better than Plurality.
Although there are many other methods that are better than
Plurality, there are no others that are
uniformly better, i.e. no other method Pareto dominates Plurality.
When we propose a method to replace Plurality, if that method is
worse than Plurality in any aspect at
all, you can be sure that the opponents will focus on that aspect.
A reason for caution BUT it is proper to consider magnitudes of both
gains AND losses.
But who can rationally oppose a change to a method that is uniformly
better than the status quo, except
by proposing what they think is a better method? But that supposed
better method can be shot down if
it is worse than Plurality in any aspect. Take IRV, for example.
It has more complicated ballots than
Plurality. And unlike Plurality it fails monotonicity, just to
mention two aspects. No matter that its clone
independence and later no harm features may completely compensate in
the minds of some people; it is
not uniformly better than Plurality.
Even DYN which is a hybrid that allows Asset voting at one extreme
and Approval at the other is not
uniformly better than Plurality, because the ballot is slightly more
complicated. In every other way it is
better than Plurality, Asset voting, and Approval. So far I have
seen no method that is uniformly better
than DYN, but the trouble is that DYN is not itself uniformly better
than Plurality because it needs a two-
bits-per-candidate ballot instead of a one bit per candidate
ballot. Our voting public may not be ready for
that much change in the ballot. All of the other proposed methods
except various three slot methods
like MCA use more complicated ballots than DYN.
Is DYN too complicated? If so, we are stuck with ordinary Approval
or ordinary Asset Voting. They are
the only choices simpler than DYN that dominate Plurality.
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