[EM] Testing 1 2 3

James Gilmour jgilmour at globalnet.co.uk
Fri Jan 2 07:53:01 PST 2004

David Gamble wrote:
> I would like volunteers to test  this model and give their 
> comments on it. If you would like a copy of the model to test 

No test is possible because you have not specified the criteria against which you wish to test the

If your criterion is proportionality of party, all the multi-member systems will perform better than
any of the single member systems, except by chance.  The degree of deviation in the single-member
systems will depend on just how you allocate the votes to the single-member districts.

If you want the highest possible degree of proportionality of party, D'Hondt Highest Average ( 1
fifty member district) will give a better result than D'Hondt Highest Average (5 member districts)
or STV (5 member districts).

If you maximum voter choice among all candidates, STV (5 member districts) will allow that in a way
than none of the other systems will.  But that feature will not be demonstrated in your model.

The answer you will get will depend on the criteria you set for your test.

Which criteria you "should" use has little to do with voting systems per se, but is essentially a
political decision.  The importance different commentators and analysts attach to the various
possible criteria is usually a reflection of the political culture (or the political agenda) of the
commentator or analyst.

So some analysts attach great importance to party proportionality. Some want that PR expressed to
the maximum possible degree at national level (one national district).  Others want to reduce the
effects of the party machines and maximise voter choice.

PR (of parties and of anything else in systems that allow such expression) will always be better the
larger the number of members per district, but there is trade-off between the degree of
proportionality and localness of representation.  Where that balance is to be struck is a matter of
political judgement, and decisions on this differ very greatly in different communities.

So define your criteria, and then evaluate your voting systems against them.

Incidentally, I was surprised to see Borda included in your list.  Borda is so fundamentally flawed
that I don't think anyone will ever use it for public elections  -  at least, I hope not.  Whether
the flaws will be obvious in your model will depend on the datasets you have chosen and on the
allocation of votes to districts.


More information about the Election-Methods mailing list