Tuesday, July 5, 2016

Election results madness

With help from the AEC scraping code by Mick McCarthy here, I've tried to predict the election results once the "non-ordinary" votes (early, pre-poll, postal and provisional) have been counted. These tend to go more for the Liberal party, so seats that Labor is currently ahead in might be lost. 

I’ve assumed that:
  • all ordinary votes are in (only non-ordinary votes left), 
  • the proportion of formal votes remains the same as in 2013 for all electorates, 
  • the number of non-ordinary votes all increase proportionally with each other, 
  • and the changes in 2 candidate preferred votes between voting types (I call this "bias") in each electorate stay the same between 2013 and 2016 (e.g. if the Libs get a 2% bounce in postals in Denison in 2013 compared to their ordinary vote result, that same proportion holds in 2016).
It turns out that William Bowe of the Poll Bludger, my favourite election analysis page, pipped me to the post with his analysis here, but I thought I'd run mine anyway. And it gave similar results, but importantly different enough to get the Coalition over the line. Here are the number of votes that the LNP (Liberal/Nationals party, well, Coalition) are expected to be ahead or behind in the closest seats:

Capricornia LNP +547
Chisolm LNP +1230
Cowan LNP -580
Flynn LNP + 1469
Forde LNP +86
Gilmore LNP +713
Herbert LNP -315
Hindmarsh LNP -786
Melbourne Ports LNP -1224 (I didn't do 3CP analysis though...)
Petrie LNP +1447

The Poll Bludger's analysis has them behind in Forde by 18 votes - my extra seat gives them 76 seats, a majority in their own right, whereas his 75 seats is not enough.

I then had a play with adding random variation, relaxing the assumptions of the proportion of formal votes staying the same and the amount of bias staying the same. I assumed that the overall variance between electorates for these properties stayed the same, but that a little (10%), half (50%) or all (100%) of the variance was due to random variation and not the specific effect of being in one electorate or another. The less important electorates became, the less likely a Coalition victory - for a little, 66% of simulations resulted in a win; for half, 34% and for full random variation, only 20% of cases.

Edit: Using 2010 results instead give us similar results, though slightly worse for the Coalition - 76 seats for the Coalition without variation, and 53%, 20% and 16% in the three scenarios described respectively.

Edit #2: Using 2007 results is more difficult because of seat redistributions, but we can do it if we assume that Liberals and Nationals will experience the same swings in Capricornia and Flynn. The model also gives 76 seats for the Coalition without variation, and 91%, 49% and 27% for the scenarios.

The model also pointed to some seats that could potentially be very close (winning 2PP < 50.2%) in these situations, so watch for these potentially coming into play if things get even more interesting:

Batman (VIC)       
Longman (QLD)

Banks (NSW)
Dickson (QLD)
Dunkley (VIC)
Griffith (QLD)
La Trobe (VIC)
Lindsay (NSW)
Robertson (NSW)


  1. Really do not think it wise for yourself or Mr Bowe to in any way compare 2013 results in regards to Postals for the 2016 Election...I am picking 71 or 72 seats for Labor.

    1. No argument there - for me, it was just the simplest assumption that data was available for, especially as there seems to be a tendency for different electorates to have very different postals patterns.

      If I get time (I do have a job I'm meant to be doing!) and it's not too messy I'll try it with 2010 postals. What's your pick for Coalition seats? I'm leaning more towards 75 the more I think of it, but 76 (or more!) is still on the cards...

    2. I've now added 2010 results above - it makes a small difference away from the Coalition but not as much as you might expect...

  2. Thanks for that Nick...I am no expert on these things, but as I think of it of course there was also a large swing against Labor in 2010...this time a swing to Labor, also school holidays and 'Mediscare' time will tell, I can certainly see why people would wish to smack the big 2 parties...but will never understand the appeal of One Nation......Regards Chris