[EM] PR favoring racial minorities

[Raph Frank]

On 8/22/08, Kristofer Munsterhjelm <km-elmet at broadpark.no> wrote:
>  If I understand Schulze's STV method correctly, it calculates vote
> management strengths and so does vote management on behalf of the voter and
> on all candidates. I may be wrong, though, and Schulze STV uses a very large
> amount of memory for elections with many candidates and winners. Still, it
> shows the possibility of having a method that resists vote management.

That is interesting.  I have had a look at his paper, but
the method itself seems pretty complex.

Is there a simple/basic explanation of the method?

He looks at 2 kinds of free riding.

First is Woodall free-riding.  This is where a voter votes
for a weak candidate first and then ranks as normal.

This means that if their first choice easily gets elected,
the voter doesn't waste any of their vote as their vote
goes at full strength to their 2nd choice.

Meek's method pretty much covers this version.

The other free riding method is call Hylland free-riding.
This is where the voter doesn't vote for their first choice at all
(or at least votes for them at a lower ranked position).  Unlike
with Woodall, their top choice is very likely to get elected.

It is this kind of free-riding that is hard to remove.  If the
voter votes for a 'throw-away' candidate, at least it is possible
once that candidate is eliminated to say that the voter's
real first choice was the one they voted for 2nd.

However, with Hylland free-riding, the voter doesn't vote
for their first choice at all (or if they do it is below other
'real' candidates).

He also says that vote management is basically wholescale
free-riding.

The party is trying to assign only enough party votes to each
of its candidates so that they get a quota.

Anyway, I think that vote management has 3 main
advantages for the party

- Getting candidates elected with less than a quota

If a party has 1.8 quotas worth of votes, then splitting
them equally between 2 candidates might get them
both elected.  If they were unbalanced, then one
candidate might be elected with 1 quota, but the
other might be defeated by someone with more than
0.8 quotas.

Meek's method, or even just recalculating the quota
on the fly would solve this.

- Preventing candidates being eliminated early

Balancing votes between all party candidates
reduces the chances of one of them getting
eliminated early and thus allows them receive
votes inwards.

This is the standard centre squeeze problem
as with IRV and is covered by CPO-STV.

- capturing a greater proportion of personal votes for the party

Any surplus of a candidate who easily reaches
quota will be a mix of personal and party votes.
Thus some of the votes that went to a party member
will end up being transferred away.

If less party supporters vote for the candidate, then
they can be used at full strength for other party members.
This means that that the party gets better use of the personal
vote of the member.

This is the vote management version of Hylland free
riding.  Party voters are en mass downgrading their
top choice as he is likely to get elected anyway.

Meek's method solves the first problem by adjusting the quota
and CPO-STV solves the 2nd problem by not eliminating anyone.
The 3rd one like Hylland free-riding on an individual level is
very hard to fix.  (Schulze aims for equality of effect rather than
trying to eliminate it).

Meek's method also solves Woodall free-riding, though I'm not
sure if there is a vote management method that takes advantage
of it.  A party would need to flood the constituency with 'no-hope'
candidates so there is enough of them for all of their supporters
to vote for.  That might be a little to obvious, but it could work.

None of your party's supporter's votes would be wasted electing
candidates for other parties who get elected on the first count.