So, predictions…

I’ve been keeping track of the polls with my Poll of Polls (final update here), but of course polls technically aren’t prediction devices. They ask the question, “If an election were held today/tomorrow”, and are therefore only so useful when it comes to predicting what people will do in a few days time.

Likewise, Poll of Polls’ are generally fairly slow at adjusting to sudden events. They help cancel out statistical noise, but sometimes when a party shoots up in the polls it’s not statistical noise; the party actually is significantly more popular than it was the previous day, week or month.

The rise of NZ First and the Conservatives is a case in point. The final pre-election polls from each of the five main polling companies shows a spread of 6.6% to 8.4% for NZ First (an average of 7.6%), while my Poll of Polls has them on just 6.3%, outside the spread altogether.

Likewise, the final polls for the Conservatives show a spread of between 3.3% and 4.9%, while my Poll of Polls has them on 3.3%, at the very bottom of the spread.

Then there’s the perennial issue of whether the polls are inherently biased. Are they missing important swathes of the voting population, resulting in fundamentally skewed results? My Poll of Polls adjusts each poll based on how far above or below the industry average that polling company is. It doesn’t adjust for whether the polls are inherently out in relation to election results., largely those results can change quite markedly from election to election.

There are a few bias-adjusted predictions out there. Over at the Dim-Post, Danyl McLauchlan Poll of Polls applies a significant downward adjustment to National, and a significant upward adjustment to NZ First (there are other adjustments, but those are the big ones). I think his adjustments are too large, but there you go… I guess we’ll soon know just right or otherwise he is…

Danyl has given his predictions for five parties, heavily couched with 2% bands:

  • National 42 – 44%
  • Labour 22 – 24%
  • Greens 13 – 15%
  • NZ First 7 – 9%
  • Conservatives 5 – 7% (although he further couches his prediction by noting that the recent controversy over the resignation of Colin Craig’s press secretary might drop the Conservatives below 5%).

And Gavin White has published his bias-adjusted predictions for the parties he has “good data” for:

  • National – 45%
  • Labour – 26%
  • Greens – 11%
  • NZ First – 9%
  • Maori – 1.3%
  • ACT – 0.8%
  • United Future – 0.6%

My gut feeling prediction?

  • National 46%
  • Labour 26%
  • Greens 12%
  • NZ First 8%
  • Conservatives 4%
  • Maori – 1%
  • United Future – 0.2%
  • ACT – 0.5%
  • Internet Mana – 1.9%

Now let’s see how wrong I am come Saturday night!

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