Sunday, June 10, 2018

Poll update

The latest aggregation follows. It treats the Newspolls since December 2017 as a different series to the earlier Newspolls. I have split Newspoll into two series on the basis of its treatment of One Nation preferences. The current two-party preferred (TPP) estimate, based on the assumption that house effects balance out on average, sees the Coalition on 47.8 per cent to Labor's election winning position of 52.2 per cent.



As a cross check, let's look at how this compares with a number of moving averages, which have been similarly adjusted on the assumption that house effects balance out on average. Both the LOWESS-91 and and Bayesian hierarchical model (above) suggest that the Coalition's poll position may have peaked and is now trending down.The moving averages are slower than the Bayesian to respond to changes in public opinion. They can also exaggerate the end point position.


We can also compare the estimated house biases from the various moving averages compared with the Bayesian model above.

Essential Ipsos Newspoll Newspoll2 ReachTEL Roy Morgan YouGov Iter Sum Errors Squared
Model
HMA-181 -0.805492 -0.864758 -0.792727 0.073339 -0.324017 0.511941 2.201714 22 0.008374
HMA-365 -0.781727 -0.742800 -0.723322 0.054020 -0.300477 0.293336 2.200970 20 0.009416
LOWESS-91 -0.801099 -0.883610 -0.807314 0.132668 -0.290249 0.443300 2.206304 19 0.008246
LOWESS-181 -0.803521 -0.804463 -0.770847 0.111452 -0.311898 0.369247 2.210029 16 0.009263

Let's move to the TPP analysis based on primary votes and preference flows at the last Federal election. This use of preference flows is less favourable to the Coalition than the latest flows at Newspoll. We are not seeing a downturn in any of these series. This might be the additional constraints in the primary vote model makes it less responsive to chnages in public sentiment. But this might be because the model does not take account of One Nation preference flows separately from other parties in the others category.


The primary vote share estimates follow.





Separating One Nation from Other above ... we can see a party that appears to be in decline, and well down on its peak in early 2017.


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