Monte Carlo simulation

At the start of the campaign, I ran a Monte Carlo simulation of the election. I thought it would be interesting to run it again with the latest Newspoll data. This simulation is based on a 49 per cent two-party preferred (TPP) vote share for the Coalition.

But first some caveats. My Monte Carlo model is very simple. It does not make adjustments for the sophomore effect (a second election bounce for first-term members running for re-election), nor the retirement effect (a loss of party support when a long-term member retires). The model also makes use of an experimental application of the Dirichlet distribution to randomise state swings within a constrained national swing.

The most likely result is Labor would win 80 seats and the Coalition 65. I have allocated six seats to others (two from Labor and four from the Coalition). This is much closer than it was at the start of the election campaign (Labor 87 to Coalition 58) and reflects a significant tightening of from Newspoll over the last three months.

The full set of probability outcomes for Labor and the Coalition from the Monte Carlo simulation is as follows. There is some possibility of a Labor minority government. Much of the distribution comes from the risk of a polling failure.

In terms of the Cube Rule, this suggests Labor would only win 78 seats from a national TPP vote for Labor of 51 per cent. Again I have allocated six seats to others.

My adjusted state swings were as follows. These are the swings to the Coalition in percentage points for each state from that state's 2016 TPP vote share for the Coalition.

The seat-by-seat TPP results follow. This includes seats which would be won by the other party on a two-candidate preferred basis.