SA 2010: Batch simulation Monday, March 15, 2010

Continuing my coverage of the South Australian 2010 Legislative Council Election, here is the batch simulation of the election.

Methodology

A batch of 20,000 simulations with a standard normal distribution applied to each party's vote (with a underlying primary vote based on a sythnesis of galaxy and newspoll). Basically, we run 20,000 simulations and each time change the vote of each party by a small random amount. This should allow us to see which parties are most likely to rise to the top. As a rule of thumb, if I, a non-South Australian, had heard of the micro party candidate I gave them 1% of the vote, else 0.1% of the vote. So David Winderlich, Save RAH, FREE Australia, Gamers4Croydon, Shooters, DLP all got 1%.


Results
The most common outcome, occurring 48.3% of the time, of the 20,000 simulations is Family First 1, Australian Greens 1, Labor 4, Liberals 5. The second most common outcome, occurring 39.5% of the time, is Family First 1, Greens 1, David Winderlich 1, Labor 4, Liberals 5. A distant outside chance, occurring in 10.2% of simulations is the Greens winning 2 seats.

Read more after the jump...

The full table is below:

Combination	Simulations
FF,Greens, Labor x 4, Liberals x 5	9655
FF,Greens,Winderlich, Labor x 4, Liberals x 4	7908
Greens,Greens, Labor x 4, Liberals x 5	1283
FF,Greens,Greens, Labor x 4, Liberals x 4	750
Dignity for Disability,FF,Greens, Labor x 4, Liberals x 4	274
FF,Gamers4Croydon,Greens, Labor x 4, Liberals x 4	60
FF,Greens,Christians for Euthanasia, Labor x 4, Liberals x 4	26
FF,Greens,Henderson, Labor x 4, Liberals x 4	13
FF,Greens,Legalise Euthanasia, Labor x 4, Liberals x 4	11
FF,Greens, Labor x 4, Liberals x 4,United Party	10
FF,Greens,Williams, Labor x 4, Liberals x 4	7
FF,Greens,Ienco, Labor x 4, Liberals x 4	1
FF,Greens,Aldridge, Labor x 4, Liberals x 4	1
FF,Greens,Social Env and Econ Justice, Labor x 4, Liberals x 4	1

Conclusions
The stand out quirk here is the high standing of independent David Winderlich. On only 1% of the vote, he wins a seat in nearly 40% of simulations. And his win comes not at the expense of Family First or the Greens, but of the Liberals.

The Liberals still win a 5th seat in 60% of simulations.

Now I'm wondering if I made a mistake of giving 1% to high profile micros and independents. As established in a post last month, the micro candidate that out-lasts the others will most likely win a seat, so giving some 1% and others .1% does not show the value of their respective preferences deals. A better batch would be to have all the micros on the same vote, say 0.5% and see which one rises to the top.

On a side note, Antony Green has finally put up his tax-payer funded LC calculator. It's a bit primitive compared to cassandra (my simulator) but it's good for casual use. heh.