Monday, 16 February 2015

Summary (Davneport and Queensland State)

I’ll keep this quick and simple, because there isn’t a whole lot to analyse. We correctly predicted a Liberal victory in the Davenport by-election. So that’s nice, but doesn’t allow for much introspection.

In Queensland we made predictions for 85 of the 89 seats and got 75 correct. That’s 88.2%, which is a little lower than I’d usually like but it was an odd election, which was a correction for an even odder result previously.

Moreover, the standard polling got 74 of their 84, which is only 88.1%. So on the comparative scale we’re marginally ahead.

I was hoping to see which of the lengthy list of methods from the prediction bested the standard poll-and-pendulum approach and which didn’t, but in the end there were only 5 seats where one method beat the other.

Where we did well: Gladstone, Nicklin and Noosa. These are the three seats we did better than the standard method. Slightly unsatisfyingly, these were all tossups for the pendulum due to the existing 2PP margin not being an ALP v LNQ contest.

The three pendulum tossups we called, we called correctly. By contrast, the two of our tossups the pendulum called (Kallangur and Pumicestone) they got wrong. So we’re better at choosing our tossups. That’s something. Right?

So, how did we choose who to back in these tossups? Historical data.

In Nicklin, the Independent had been in since 1998 and had held off the Liberal National surge of 2012. Gladstone’s Independent was retiring, and had only ever been ALP prior to that.

Noosa was a little harder. But then Noosa was odd – a Coalition v Greens 2PP vote in 2012 but’s the seat high on my list of oddballs. The seat had had 6 Liberal/LibNat victories and 2 Labor wins. That’s a bias but not a conclusive one, especially with the anti-LNQ sentiment of recent Queensland politics.

Although we did discuss the problems with this approach – a strong ALP history for a seat created during the long line of recent ALP victories might be stalwart or bellwether – the polling did actually land slightly more LNQ-leaning than the historical trend, so if anything the seats would be more LNQ friendly than in the past.

Where we did badly: Chatsworth and Everton. Polling had both of these as LNQ wins, but we backed the ALP. Why? Historical data.

Both seats had only one ALP loss since 1977 (i.e. the 2012 abberation). However, throughout that time 1986 was the only election where Labor was not either:
gaining seats, or
the party that went on to govern Queensland.

Other seats in this position include: Brisbane Central, Bulimba, Bundaberg, Cairns, Cook, Ipswitch West, Lytton, Mackay, Murrumba, Nudgee, Rockhampton, Sandgate, South Brisbane and Woodridge. It’s tempting to say that the methodology was sound since we correctly picked all of those. Tempting, and wrong.

First, remove those with even longer-term ALP support (support when the ALP was not in favour). That leaves: Brisbane Central, Murrumba and Woodridge (and maybe, just maybe, Lytton and Rockhampton). And Brisbane Central was only introduced in 1977, so it’s hard to say whether or not this one would have been removed had it had a longer history.

Then scrap Woodridge, because that stayed with the ALP in 2012. That leaves us with Chatsworth and Everton wrong and Brisbane Central and Murrumba correct. 50:50. Compare that witth the poll-and-pendulum which got all four right.

So, while electoral history is very useful – in picking tossups at least – it needs to be tempered with a broader understanding of the state’s political slant. This was something we tried around this time way back in 2014 for the SA state election, and something we will return to for the NSW state election on March 28.

Hopefully I’ll have updated this blog’s allegedly running tally of correct predictions by then.

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