[EM] Testing 1 2 3

James Gilmour jgilmour at globalnet.co.uk
Sat Jan 3 03:13:01 PST 2004

> James Gilmour wrote:
> >I think there is another very real problem here.  It is not 
> clear from your original post >whether your model will modify 
> the voting patterns under the 11 different voting >systems, 
> but my reading would be that it would not.  We know from 
> practical >experience that real voters do change their voting 
> patterns when you change the >voting system.

David replied: 
> I thought somebody was going to make this point, it is of 
> course true that voters change how they vote according to the 
> system they are voting under. I have assumed that they vote 
> sincerely and the same regardless of the system because this 
> is the only real way to make a comparison.

This may be only way you can make the comparisons, but unfortunately it tells us little about the
"real" effects of different voting systems.  Accepting sincere voting in all cases, voters will vote
differently under different systems, even when they have the aim of achieving the same outcome in
terms of representation.  The best voting pattern to achieve that end will differ under different

And, of course, different voting systems present different opportunities to voters and voters would
be stupid not to take these opportunities when they have them.  Sometimes they get it badly wrong,
through bad advice or ignorance, but sometimes they get it spectacularly right  -  "right", that is,
from their own perspective.

It is not quite the same as the purpose of your comparison, but we have had some very good examples
of this in the elections for the Scottish Parliament and our local Councils.  These elections are
held on the same day, by two different voting systems: our version of MMP for the Scottish
Parliament and FPTP for the Councils.  The only way some results can be explained is that in parts
of Edinburgh the same electors voted Liberal Democrat for their local councillor, Labour for their
constituency MSP and Green for the regional list MSP.

Now you know why I avoid modelling and instead analyse only the results from real elections.

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