Possums Pollytics

Politics, elections and piffle plinking

Modelling the Howard Governments Primary Vote Swing

Posted by Possum Comitatus on July 3, 2007


The above graph measures the primary vote swing of the Howard Government since its inception in 1996.The way it works is quite simple, each of the dashed vertical lines represents an election. The blue line represents how far away the governments’ primary vote is from the primary vote it received at the election most recent from the observation. So if we take the observation of March 2001 as an example (the bottom of that negative spike in the shaded blue area called “One Nation residual effect), that tells us that the Howard government in March 2001 was, according to the Newspoll estimate of primary voting intentions, experiencing a 3.5% swing against their primary vote based on the primary vote they achieved at the 1998 election. This is a result of the government receiving a primary vote of 39.5% at the 98 election, and getting a Newspoll estimated primary vote of 36% in March 2001.

For anyone that would like a little more of an explanation of the swing graphs, you might want to head over to Part 1 and Part 2 of Into The Swing of Things to get some more detail.

But what I want to focus on today is explaining the primary vote swing of the Howard government since its inception in 1996.The yellow shaded area above called “One Nation Vote Effect” represents the impact on the governments’ primary vote that One Nation was responsible for. Once the One Nation “Party” was created (in its various types of organisational structures), the governments estimated Newspoll primary vote took a beating as conservative votes moved across to One Nation from the Coalition.

But because the above graph measures the primary vote swing, One Nation had a lasting impact on the swing beyond the 1998 election. As One Nation caused the governments primary vote to be a low 39.5% at the 1998 election, and the “swing” measures the difference between any given Newspoll and the primary vote received at the previous election – that low government primary vote at the 98 election caused by One Nation had the effect of artificially inflating the swing size for the period between the 98 and 2001 elections.

As a result of this, any modelling of the swing must take into account not only the direct One Nation vote effect (which was voters moving from the Coalition to One Nation) but also the residual One Nation effect (which is the low government vote at the 98 election caused by One Nation that flows through to the artificially high swing numbers for the government primary vote from the period November 1998 through to October 20001).

I’ll use two separate regression equations to model the government swing. First a model that calculates the swing based on changes in the Newspoll estimation of the Prime Ministers satisfaction rating, a cubic time trend and two dummy variables to account for the One Nation vote effect and the One Nation residual effect.

The second regression models the government primary vote swing on the changes to the Prime Ministers satisfaction rating, a linear time trend and three dummy variables accounting for the One Nation vote effect, the One Nation residual effect and a dummy variable representing the “Rudd Effect” (which will estimate the change in the government primary vote swing that can be explained by Rudd becoming leader in December 2006).

For the first model, it can be represented as:


Where PVSGOV=Government Primary Vote swing at time “t”

PMSAT=Prime Ministers satisfaction rating at time “t”

The “t” variables represent the cubic time trend and the two One Nation dummy variables are self explanatory.

In the model output below, “time” is represented as “HTIME”, meaning it starts at 1 in the first month of the Howard government and increases by 1 for each month his government has been in power.




There’s a lot of explanatory power in the model (even accounting for degrees of freedom for those of you with a stats bent).Graphically combining the modelled behaviour against the actual government primary vote swing, and looking at the “residuals” which are the differences between the model behaviour and the actual values for each observation we get:


Before we analyse this, let’s do the other regression model so we can look at them both together. This second model we are basically replacing the cubic time trend with a linear time trend and an explanatory variable for the Rudd leadership, represented as:




Again, this model like the first explains quite a lot. About 86-87% (accounting for degrees of freedom) of the change in the governments primary vote swing can be explained by time trend movements, PM satisfaction levels and dummy variables.

The fact that both a cubic time trend and a linear time trend combined with a Rudd variable explain a hell of a lot of the governments primary vote swing over recent times suggests to me that Rudd isn’t the driving factor for the ALPs recent vote juggernaut, but rather Rudd is merely the vehicle for allowing the underlying sentiment against the government that has been around for years to manifest.

The media pundits and parts of blogsville have been acting all surprised that the electorate have somehow “turned” on the government out of the blue. But as has been demonstrated here before time and time again, it’s not out of the blue. There has been a consistent and growing swing away from the governments favour since the 98 election with the swings to them trending less and less positive, before turning negative, then turning against them in larger magnitudes.

They nearly lost in 1998 – securing less than 50% of the two party preferred vote.

They nearly lost in 2001, with some serious porkbarreling and the Tampa/S11 riding to their rescue, giving them a primary vote spike which was volatility off the longer term trend running against them at the time.

Over 2001-2004, 5% of the government primary vote went AWOL and stuck mostly with the minor parties and a bit to the ALP, but the ALP under Beazley and particularly Crean couldn’t grab those AWOL coalition votes. Latham came along and grabbed not only that 5% of ex-coalition voters parking with the minors, but also 3% extra from the Coalition primary vote. Latham imploded and that 7-8% went back to the minors and the Coalition. Not because of Howard, but because of Latham.

Approximately 30% of swinging voters deserted Howard after the 2005 budget, taking 5% off the governments primary vote which went straight to the Minors and undecided camp (and none of them have come back since), and another 3% thereabouts shifted between the ALP, the Minors and the Coalition on a regular basis.

Along came Rudd and the underlying trend away from the government crystallised into an ALP primary vote lift (rather than the minor parties +undecideds where it had been hiding for the last 5 years to varying strengths).

The primary swing models above, plus the approximations of the swinging voter movements, plus the time trends of the primary votes, plus the larger swings for the parties all point to the turn against the government not being new at all, but being a larger, longer trend way from the government where people have been looking for a long time to place their votes elsewhere than the incumbents.

Beazley never cut it with the electorate after 2001 – every piece of PRIMARY data shows that, from the ALP primary vote numbers to the primary vote swings, to the minor party primary vote numbers. Voters often left the Coalition, but after 2001 they never went near Beazley again.

Crean never cut it with the electorate, period. The Coalition lost voters under Creans time, but they went to the minors. Only a bloated two party preferred estimate coming off large minor party preference flows made Crean seem not completely and utterly hopeless. TPP polling estimates are dodgy at the best of times – which is why I don’t touch them with a barge pole.

Latham had the electorate and imploded.

Rudd on the other hand cuts it with the electorate and like Latham, only an implosion will stop him from becoming PM, as only an implosion can give the government the volatile spike they need to gather enough votes from the longer term time trend in electoral support that is running strongly against them.

Will Rudd implode?

I can’t see a handshake of doom coming from the man, nor signing giant cardboard pledges guaranteeing interest rates or any of the other political flapdoodle encephalitis that inflicted the brains of Latham and the advisors around him at the time.

As the primary vote swing models above show clearly – once you account for One Nation effects and take into account the non-linearity of the PM satisfaction levels where he’s becoming more disliked over time, the trend in the swing of the governments primary vote is, and has been for years, running against them.

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8 Responses to “Modelling the Howard Governments Primary Vote Swing”

  1. Kina said

    I was only commenting today in another blog that it seemed like the electorate was waiting for Howard to be taken down so the rest could stick the knife in and engage in a feeding frenzy to make sure he was finished off. Rudd is the vehicle and if the steam increasing in The Australian’s blogs is any indication then people cant wait to start jabbing while reciting his sins, Hicks, Tampa, Iraq etc.

  2. electa stone said

    Your model depends heavily on your slicing of the data into periods and labeling these as the ON, post-ON and Rudd effects. This weakens its predictive capacity (you do not know or not wwhether next month wi;; begin the Howard resurgence effect).

  3. Possum Comitatus said

    Kina – the changing satisfaction results of the PM is interesting, in that its not one key issue that seems to be causing it, but a whole grab bag of gripes that are different for different people, but all contributing to the same effect.

    Electa – the One Nation periods were sliced on those exact dates for a reason.The One Nation vote effect starts on the month that the ON party effectively formed and became an available choice in the Newspoll poling (which is the figures I’m using between elections).The One Nation residual effect started the first day after the 98 election and ended on the day before the 2001 election simply as a result of the “swing” being counted as the difference between any given Newspoll value and the vote achieved at the election previous to it.The “Rudd effect” likewise is not arbitrary – the Rudd effect series has a value of zero for the months Rudd wasnt the leader, and a value of 1 for the months he has been leader.What it captures and allows to be explained is the observable large movement in the polls that has occured since Rudd became leader.

    As a model, its not predictive (I deliberately didnt do any numerical forecasts for it), but simply descriptive.It attempts to describe the observable reality witnessed since 1996 for the governments primary vote swing.

    I have no doubt Howard will launch some type of resurgence, all this model attempts to do is to crystallise out some of the underlying factors in that primary vote swing movement that might be a good idea to keep in ones thought orbit when thinking about the size of the resurgence Howard needs to pull off an election win, and how much those underlying trends and factors are working against his eventual attempt at a resurgence.

  4. […] the PM’s numbers weren’t doing anything to bring them back (again, thanks to Possum for fleshing out the numbers and allowing me to breathe a little more […]

  5. lurker said

    What about a variable for the election number the government is contesting? That would have to be significant surely – there hasn’t been a one term govt since WWII so that probably saved Howard’s bacon back in 1998.

  6. Possum Comitatus said

    I’d need a few more elections to be able to use that as a specific variable as regressions work better the more observations you have.

    The reason I used the time trend in the models was as an attempt to incorporate that very “ageing factor” of the government, so the information that an election variable would contain is actually folded into the information that the time trends add to the regressions.

    There’s more on the differing time trends of the Howard governments primary vote and the nature of their shape and influence over here if you’re interested:

  7. I enjoy what you guys are up also. Such clever job and reporting! Carry on the terrific works guys I have incorporated you guys to my own blogroll. I think it will increase the value of my own webpage 🙂

  8. Tanks To Information,, Mmmmmuach..

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