Possums Pollytics

Politics, elections and piffle plinking

ALP Victory Index

Posted by Possum Comitatus on June 6, 2007


This index represents whether the ALP would have won an election were it held at any time since December 1985.If the ALP score is above zero, it would have one, if it was below zero it would have lost.

The elections are shown on the graph, as is an assumed date of November for a 2007 election.

This index (which successfully accounts for every election result since the 1987 election) suggests that the ALP is better placed to win this election than any party has been for 20 years.

The index was constructed in two parts; a separate index that measured primary vote levels as determined by Newspoll and a second index that measured satisfaction differentials again, as determined by Newspoll

For the primary vote index, a series was constructed that measured how far away the ALP primary vote was from 40.It’s generally held that the ALP needs to get above 40 to win an election without some extraordinary circumstances such as that which prevailed in the 1990 election. So we’ll use 40 as our baseline.

This “above or below 40” series was then normalised by subtracting the mean from each observation of the series and dividing by the standard deviation of the series.

Next I took the Coalition primary vote series and did the same thing, except whereas I used 40 for the ALP, I used 43 for the Coalition. Because the conservative vote isn’t as split as much as the non-conservative vote with minor parties, unless there is a group around like One Nation that attracts a large share of the minor party vote, the Coalition cannot win if its primary vote is below 43%.

Next, a problem came up – the One Nation vote had distorted the historical Coalition primary vote series. To accommodate for this I tested the size of the vote that One Nation took away from the Coalitions primary vote using a number of regression models. They all suggested that One Nation reduced the Coalition primary vote between 5.5-6.2% during the period May 1997 through to just after the 1998 election.

With this info, I then adjusted the “Coalition above or below 43%” series for the period May 1997 through to the end of the 1998 election to accommodate for the One Nation effect on the Coalition. This final series was then normalised.

This gave me two modified series. A normalised ALP primary vote series with a zero value representing a primary vote of 40 and a normalised Coalition primary vote series, adjusted for the One Nation effect, with a value of zero representing a primary vote of 43%.

I then subtracted the Coalition series from the ALP series to give me a series called ALPtoWin1 which represents the relative strength of the ALP compared to the Coalition in terms of their primary vote.

Next up I used satisfaction and dissatisfaction levels as determined by Newspoll for each party going back to December of 1985.I subtracted the dissatisfaction levels from the satisfaction levels of each party to give me a Net Satisfaction rating for each party.

Those net satisfaction levels were both normalised, and the Coalition normalised series was subtracted from the ALP normalised series to give me a series called ALPtoWin2, which represents the relative satisfaction levels of the ALP compared to the Coalition.

I’ve been playing around over the last few weeks with finding the explanatory power of all manner of variables on primary voting movements. In order to keep this post from being a thesis length, basically the relative primary voting performance of the two sides of politics has twice the explanatory power that satisfaction differentials do when it comes to determining elections. As a result, to keep the components of this index realistic, the satisfaction index “ALPtoWin2” was divided by two to give it a realistic weighting.

Finally the simple bit – we just add the two components together to give us the ALP Victory Index.

How well does it work?

Here are the results for the elections since 1987.If the ALP gets a positive index number it should win the election, if it gets a negative number it should lose the election.

July 1987 = 1.54 ALP win

Mar 1990 = 0.76 ALP win

Mar 1993 = 1.51 ALP win

Mar 1996 = -1.60 Coalition win

Oct 1998 = -0.0016 Coalition win (just)

Nov 2001= -0.50 Coalition win

Oct 2004 = -0.60 Coalition win.

The October 1998 result is interesting as the ALP actually won a higher two party preferred vote than the Coalition, even though the Coalition retained government. I was surprised the index worked for that election.

The current value of the index has the ALP on 7.233.That is the highest value the ALP has ever had since the series starts on December 1985, and it is also higher than the absolute value of any Coalition score, even during the 1991 recession when the ALP vote and satisfaction ratings tanked.

Considering the nature of the previous movements of the index, it doesn’t look possible for the Coalition to turn that around in the time available. This too, like Election Prediction Model 1 posted earlier on the blog, points to a Rudd victory.


It was asked if a close-up of the 2001, 2004 and 2007 periods could be done to help gauge the magnitude of the turnaround Howard needs to make.

Here they are:








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14 Responses to “ALP Victory Index”

  1. Mad Dog said

    Possum, Great stuff for Howard despisers like me. Can you please clear up a little bit of ambiguity for me. Looking at the Oct 2004 figure in your list, is there a minus sign missing? And at the beginning of the third last paragraph, I presume you are referring to the Oct 1998 result, where Beazley had a TPP ‘win’ but lost. By the way, I reckon he would have won, except some genius persuaded him to come out with a promise to raise tariffs on 4WD’s to the same as ‘normal’ cars, three weeks before the election. Did wonders for the ‘Howard Battlers’ vote.

  2. EconoMan said

    Interesting stuff.

    You say that “it doesn’t look possible for the Coalition to turn that around in the time available”. It’s a little hard just with the eyes, so could you please compare the dips before 2001 and 2004 with the ‘dip that would be required’ for Howard in 2007. In particular, the time it took for those two dips.

  3. possumcomitatus said

    Doh! Slippery fingers.

    The 2004 election was actually -0.603415563. That’s much better – thanks for pointing that out.

    I meant October 1998 in the TPP.I’ve fixed that up too.It also predicted correctly the 1990 result which was 50.1 to 49.9 in the Coalitions favour, yet with the ALP retaining government.

    The mistakes made by the ALP in election campaigns over the last 10 years could fill a warehouse – no wonder they have been in Opposition for so long.

  4. possumcomitatus said

    Economan – I hope that helps the eyes.

  5. EconoMan said

    Thanks Possum. That shows that in 2001, from March to September (roughly) the ALP index dropped 8 points. The same drop, over the same time, would give a close coalition win in November/December 2007. However, I agree that the years are substantively different. The index is higher in 2007, and more sustained / consistent.

    By the way, am responding on Murray darling, but it’s long and other things keep getting in the way.

  6. cortexvortex said

    If you feed in the galaxy numbers as though they were Newspoll ie 53:47 what does the graph look like then? is it the good news the howard lovers want? my guess is no.

  7. possumcomitatus said

    The coalition moved the index 7.31 points from the end of March 2001 to the end of September 2001.The need to move the index from its current 7.23 points, which in the same time frame would make it -0.08 at the end of November.That’d make it very very close.

    In September 2001, Tampa and 9/11 took 3.37 points of that index in a month.The only time that larger monthly movements in the index happened seemed to be the result of leadership changes.

    Maybe someone should tell Costello 😉

  8. possumcomitatus said

    Convexvortex – I dont have the Galaxy numbers, I use only the Newspoll numbers because they:
    Firstly make a long and consistent series and secondly I can use them back to December 1985.

    A single poll is really pretty much irrelevant, it is the changing trend in consecutive polls that contains information.If the last Galaxy poll was representative of a trend, it will show up in Newspoll over the next month or so – which will in turn show up in the index over the next month or so.

  9. Stig said

    Very nice work. Looks like a very handy tool.

    If I can comment on the three lower graphs – please plot them so that the y-axis is to the same scale. That would help in comparing them, and better shows the magnitude of what is happening now.

  10. Paul said

    I second the request that the last three graphs be shown on the same scale… great and interesting work otherwise!

  11. possumcomitatus said

    Good idea on the graphs, I’ve fixed them up.

    I keep forgetting that when I look at the graphs they’re all perfectly scaled in a stats program, but when you guys get to look at them they can resemble a dogs breakfast.I’ll try and keep that in mind in the future.


  12. gusface said

    as a sidepoint maybe graph the tipping poll at ozpolitics
    at moment 20 tip Lib victory
    40 tip Lab victory
    vary margins of course
    history ie last 3 mths would be interesting
    Just an idea 🙂

  13. lurker said

    The peak in 2001 came in March, at the height of the GST dissatisfaction, from memory Howard removed the indexing on the petrol excise around then and his fortunes began to improve from that point.

    Something similar hasn’t happend so far this year, will it need another Tampa/September 11 for Howard to win?

  14. possumcomitatus said

    Tampa and 9/11 got Howard a 3 point boost in the index, probably 4 with its after effects (although determining how much of the follow on movement was due to those events, how much was due to Howard and how much to the ALPs mishandling of them is a bit more difficult).

    But even if Howard found a great diversion – say, like some bunch of swarthy refugee-terrorist types hijacking a plane, crashing it into Jennifer Hawkins backyard, beheading her dog and holding her hostage in front of Today Tonight cameras.

    I cant see the public running back to Howard anymore over stuff like that – especially since most of the public reckons things like Iraq have made Australia a bigger “terrorist target” according to the polls.Maybe we’ve grown up, maybe we can see bullshit better these days. Either way, I think Howard needs more than a Tampa, he needs Rudd to be caught with a dead girl or a live boy as the US saying goes.

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