Sunday, April 12, 2015

Aggregated polling update

Another set of noisy polls - moving in different directions - giving different messages on the state of the nation's voting intentions:
  • Newspoll over the weekend is unchanged on three weeks ago with the government on 49 per cent.
  • Ispsos over the weekend has the government down three points on the end of February at 46 per cent.
  • ReachTEL at the end of March, had the government up one point on the beginning of February at 46 per cent.
  • Morgan at the start of April had the government up three points on the middle of March at 47 percent.

Using the Bayesian model to peer through the polling noise and house effects suggests there has been little movement for six weeks in the government's polling fortunes.

If we adjust the recent polls for house effects, an interesting pattern emerges. Very few of the recent polls are close to the median model prediction. A cluster of adjusted polls sees the government on 48.5 to  49 per cent. Another cluster of adjusted polls sees the government on the very uncompetitive 44.5 to 45.5 per cent. I am not sure that this is meaningful, beyond being cautious and acknowledging that the polling seems quite volatile at the moment.

I also use a less-sophisticated localised regression (LOESS) as a cross check. The end-points in the LOESS regression are very volatile, and the technique is overly sensitive to endpoints and outliers. At the moment, the LOESS regression is telling a different story to the Bayesian model. However, my experience is that the LOESS model usually comes into line with the Bayesian model as more data points are added. I would be cautious with a recovery narrative based solely on the LOESS regression. Noting the Bayesian bifurcation above, a recovery narrative for the government over recent weeks cannot be ruled out; but nor can it be proclaimed as absolute fact. All we can do is patiently wait for more data points. 

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