Thursday, 23 November 2017

Rainbows and Sunshine

The Queensland state election is tomorrow, but first a very brief reflection on the results of the same-sex marriage survey:

A Very Brief Reflection on the Results of the Same-Sex Marriage Survey

Polling had indicated a 64% 'Yes' vote with some 5% undeclared. Assuming this 5% split as per the declared votes, this would be around 67%. Since this was the only data we had, there wasn't much scope for numerical analysis. On a gut instinct, though I suggested around 61% 'Yes'.

The actual result was 61.6% 'Yes'. I feel pretty good about that, but since it wasn't based on anything I can't really apply this going forward.

I told you I'd be very brief.

Queensland State Election

It's the election of the only house of parliament in Queensland tomorrow, and it's reported to be a close race. This time around I'm going to try a few different approaches to how I extrapolate from the pendulum. We have two starting points: the lay of the land after the 2015 election, here, and the updated but theoretical current landscape after electoral redistribution etc. here.

As always, we will ignore the seats that are not held in a Labor/Liberal National contest when applying the state-wide swing. Obviously the relative shift between Labor and LNP popularity plays out unpredictably in seats held by One Nation, Katter and independents.

Swing from 2015 Election:

Yes, I spelled 'incumbent' wrong. I also copy-pasted that error onto most of the tables below. Lets just pretend it's a situationally valid alternate spelling, like 'capitol'.

The values in the 2015 column indicate the lead the ALP held in this seat after the election. This was after a 51.1 : 48.9 split of the public vote. The latest polling suggests the current mood is slightly stronger for Labor at 52 : 48. This is a swing of 0.9 percentage points, which is applied uniformly in the PP column.

This suggests a gain of two seats for Labor, taking them from minority to majority government assuming no change in the non-two-party contests.

To try something new, I have also added a badly-titled '%' swing column that looks at the proportion of voters who might swing. To take an extreme case, a seat with 100% ALP support under the PP column would be expected to return a 100.9% result for Labor under the PP column. The % column instead looks at the available voters that might swing. The calculation is performed thusly:

in 2015 48.9% of voters, or 489 in 1000, voted LNP in the two party preferred count. On latest polling only 480 in 1000 are expected to. This means a net total of 9 out of every 489 LNP voters has shifted to vote ALP, or 1.8%. The percentage of LNP voters in each seat can be calculated as 50% minus the 2015 margin. In the % column 1.8% of these are added to the existing Labor base.

This calculation favours the LNQ in all seats where the the ALP has a lead of over 1 percentage point, but does not actually alter the predicted outcome. (It never alters the prediction in any of the following tables either.

Swing from 2015 Polling:

There is an argument to be made that a poll is not comparable to an election result. I have therefore also calculated the swing by comparing the latest polling with the last poll before the 2015 election. This pits the latest 52 : 48 against the preceding 48 : 52, for a 4pp swing. The former is a Galaxy poll and the latter by Newspoll, but by happy coincidence the latest Newspoll is also 52 : 48, so this figure can also be used to even overlook some differences in polling methodology.

This result is calculated as above, but suggests a stronger lead by Labor.

More Recent Data:

Factoring in seat redistribution is helpful. Additionally, quite a few seats have been removed or altered so dramatically it was appropriate to rename them. This, in my opinion, makes the 2017 pre-election pendulum more accurate than the 2015 post-election one event though it is based on modeling rather than actual results.

The same methodology as above, based on the 0.9pp swing from the 2015 election, gives the following results:

And using the 4pp polling swing, we get:

Comparative Psephology

This, then, is the combined predictive result of the assumed 0.9pp swing for all current seats:

Meanwhile, using the 4pp swing we see:

Within and between these tables there are 13 conflicting predictions discussed separately, along with 9 seats not complying with the ALP/LNP two-party split.

Special Cases: Conflicts

Aspley registers as ALP when applying the 4 percentage point swing to the pre-election pendulum from 2017. While I consider this the most reliable metric I have used, every other indication is that the LNP will hold this. The seat has been held by the LNP or its predecessors in every election except between 2001 and 2009. But general discussion of the election suggests the polarising views of the Adani Mine put Brisbane seats like Aspley further in the ALP camp and rural seats in the LNQ.

This will be a close race, and certainly one to watch. If I had to pick a winner, it'd be ALP by a nose.

Bonney is a new seat with no data from the 2015 pendulum, and divided in the 2017 swings since ALP can win it with a 4pp swing, but not a 0.9pp swing. I genuinely cannot tell how this one will fall, so I'm bringing back the tossup.

Burdekin is an ALP seat by all mertics except by a 0.9pp swing from the 2015 pendulum. On the 2017 pendulum it is already an ALP seat. ALP tipped to win/hold this one.

Caloundra is an LNP seat in all metrics except by application of the 4pp swing to the 2015 pendulum, and has been since creation. The LNP margin increased after the redistribution. LNP tipped to hold.

A seat with a mixed electoral history, tipped to fall to the ALP in a 4pp swing but not with a mere 0.9pp. Another one worth watching closely. The redistribution was advantageous for the LNP, but not drastically so and as a Brisbane seat I'll tip the LNP to come out ahead.

Everton is in a similar situation to Chatsworth, but has a long ALP history and the redistribution did not favour the LNP. ALP to win.

GavenAnother Chatsworth style seat, 4pp will topple it to the ALP but 0.9pp will not. Very mixed history, with the incumbent before this one changing party three times in as many years, a brief NAT interruption to ALP roots and recent LNP success. I think I will call this for the ALP, but I'm getting nervous that a lot of would-be-tossups are falling that way when a 50-50 split might give a better prediction state-wide.

Glass House
With a 0.9% margin after the redistribution, this is on a knife edge with a 0.9pp and ALP with anything higher. ALP to win.

LNP since the 60s, LNP by all metrics except 4pp swing on redistributed figures (my favourite). LNP to hold.

Much like Bonney: new seat with no data from the 2015 pendulum, ALP can win with 4pp but not 0.9pp. Inner western Brisbane, ALP to win.

Mixed history, ALP win with 4pp but not with 0.9. Inner Brisbane. ALP win.


In threat range of the 4pp on the 2015 figures, Southport was fortified for the LNP by the redistribution. LNP to hold.

Toowoomba North
Mixed history and marginal seat, Toowoomba North will fall to a 4pp swing but not 0.9. I'm tipping an LNP hold.

Special Cases: Minor Parties

The polling is patchy as to the fate of minor parties this election. Current distribution has Katter holding Traeger with 16.1% These margin is pretty solid, and will probably resist the major parties who are too busy edging each other out in broad strokes to target minor party electorates specifically.

Katter also nominally holds Hill with 4.9% after redistribution, One Nation holds Buderim and independents hold Pumicestone and Cairns.

Hill may be an anomaly of redistribution. I expect the LNP to do well here and take the new seat.

Buderim was gained by One Nation after an LNP defection. Although the candidate may hold his seat, I expect a LNP return.

Pumicestone is neck-and-neck for the major parties post redistribution (0.1% ALP over LNP). It is listed and IND after a unendorsement of the previous ALP candidate. ALP to regain.

Cairns is Labor-leaning by history, and the current status of independent is a result of resignation from the ALP. ALP to regain.

Also of note, Gladstone is ALP v independent on 2PP numbers, with a margin of 11.89% boosted by redistribution to a whopping 25.3%. This is the easiest call for ALP on the table.

Lockyer was a narrow LNP victory over One Nation. Polling makes this hard to call, but for the sake of entertainment I'll take a punt on LNP to retain. In ON were to win, they would likely back the LNP to form government anyhow.

Noosa is fascinating for its bi-polar split of LNP v Greens. Redistribution has the margin at 6.8%, which is respectable, and the combined Greens/ALP primary vote did not rival the LNP's in 2015. LNP retain.

Finally, Calide is of note as a former LNP v PUP seat, but the fall from grace of Clive Palmer probably ensures LNP retention here.


That rounds out the predictions.

That is ALP 57, LNP 33, KAT 1 and 1 tossup. Even if some of the special cases fall unexpectedly in favour of the LNP, I would tip an ALP majority government contrary to the "neck-and-neck" headlines we are seeing.

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