Monday, August 12, 2013

Update: Newspoll 48-52 and Morgan 48.5-51.5

Today we have the third Newspoll in a row with 48-52 for the Coalition. More surprising has been the Morgan result with the Coalition ahead 48.5-51.5, calculated using preferences flows from from the 2010 Election. The Rudd restoration polls follow.

Using LOESS to take some of the noise out, the individual polling houses tell a story of a two to four week honeymoon, followed by a decline in two party preferred (TPP) voting intention for the ALP. (Note: with only two data points, I do not calculate a LOESS for Nielsen).

Collectively, the 30 day LOESS picture is as follows:

Caveats: the LOESS technique can be overly influenced by outlier data points at the end of the series. Today's endpoint is probably overly influenced by the last ReachTEL poll. It may also be overly influenced by the Morgan collapse, which at 3.5 percentage points (peak to trough) is almost double the next house at 2 percentage points.

Turning to the aggregation, we have:

Caveat: The zero line in the house effects chart is the average bias across the six polling houses I am tracking. You will need to come to your own view about where the actual level of systemic bias across the polls actually lies. At the 2010 Election (with a different set of pollsters), the population voting intention was about one percentage point more in the Coalition's favour than the pollster average (see here).

Because I have a soft spot for the grand old dames of Australian opinion polling, the Nielsen and Newspoll only (non-linear) aggregation follows ...

I will do another post tonight, after I have digested the Essential poll. (Update: perhaps Tuesday evening, as the data does not appear to have been released on Monday)

Newspoll in full

Around the web

Kevin Bonham has written a pretty good field guide to Australian opinion pollsters.

The ABC has an amusing vote compass thing.

Simon Jackman's tracking of betting markets suggests that last night's debate was not a game changer. For the three markets Simon tracks, things were essentially unchanged following the debate on the evening of 11 August.

Australian Political Betting, argues that while Labor won the debate with the pollsters, the Coalition won with the punters. To be fair, while more bookies moved in the Coalition's favour, there was not much movement. I suspect a bit of money come on following the debate, which has closed the field a little (the implied probabilities were all much closer following the debate).

Ben Raue has completed his seat-by-seat guide to the House of Representatives.


  1. Great and timely commentary as always.

    I can't help but notice that your ALP 2PP measure doesn't overlap 50% even at the 95% level (it's well clear).

    I appreciate that 2PP now is not 2PP at the election, but do you have any view on how this will translate into an election outcome?

    1. I am thinking about using the cube rule to convert the implied individual seat outcomes from betting markets to generate a TCP estimate for the September 7 poll.

  2. Thank you Mark, I am a lurker here and appreciate your expert commentary. I also check out Julian's site as well. I don't have the expertise to properly analyse polls and find your posts so much more informative than found in the main stream media.

  3. Are you using the 'beta' adjustment on the overall estimates or just on the two house version? If I understand the workings of what that is doing correctly, the beta on the Morgan Multi Poll looks like it would be significant.