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January 20, 2004

How Tough is the QLD Question?
By Senator John Cherry, with response from ABC election analyst Antony Green
January 20, 2004

There is no question that Peter Beattieĺ─˘s Labor Government enters the 2004 State Election with a thumping majority, holding 66 out of 89 seats in the Parliament. But, the electoral statistics to some extent overplay the ĺ─˛safenessĺ─˘ of Laborĺ─˘s margin due to Queenslandĺ─˘s optional preferential voting system.

The electoral pendulum published by most media outlets (including yesterdayĺ─˘s ĺ─˛Courier Mailĺ─˘) base the pendulum on the two-party preferred vote calculated by the Electoral Commission. On this basis, Labor would lose office with a uniform swing of 9.5%, with Glasshouse being the 22nd seat to fall.

But the Commissionĺ─˘s data has a flaw in it. It calculates the two party preferred vote based on the votes left in the count, excluding those votes that exhausted due to voters not allocating preferences. As a result of the ĺ─˛optional preferentialĺ─˘ voting system,  Laborĺ─˘s winning vote was less than 50% of the formal vote in 14 of the 22 most marginal seats, as as low as 41.7% in Burdekin where 24.4% of the formal vote exhausted.

Taking Burdekin as an example, Laborĺ─˘s winning majority of  1648 votes was 55.13% of the remaining two-party preferred vote. But, to overcome this lead, the Nationals need a swing of just 3.9% of the total primary vote to win, not the 5.1% shown in the pendulum. Further, if One Nation and its largely defunct offshoot the City County Alliance had run a single candidate in Burdekin instead of two candidates, they would have won the seat with a 6.2% buffer in 2001. Hervey Bay would also become a line ball seat on this basis, instead of the misleading 7.6% margin estimated by the Commission.

If the One Nation votes fell by 5% at this election in favour of the Nationals, the lower exhausting rate would see the National win Burdekin with a 0.1% majority, without winning a single extra vote off Labor. In fact, if the Nationals win a 5% vote switch from One Nation (which averaged 18% across Queensland in 2001 compared with 3% in the most recent  Newspoll and 6% in Morgan poll), the Labor seats of Noosa, Burleigh, Toowoomba North, Kawana and Burdekin all shift to the Coalition, with Charters Towers knife edge. That is without any direct swing from Labor to the Coalition but purely because of a lower level of conservative exhausted votes.

The elimination of three-cornered contests between the Liberals and the Nationals also serve to reduce Laborĺ─˘s margin in Springwood (from 10.3% to 6.8%) and Glasshouse (9.5% to 5.9%) and to a more limited extent in Thuringowa.

Finally, the Greens ran in only 8 of the 25 most marginal seats in 2001. The average exhaust rate for the Greens was 43%, with  most of their vote coming direct off Labor. This suggests that if the Greens run in any of the other 17 marginal seats, assuming a 5% vote shown in Newspoll/Morgan, they could pare up to 2% off Laborĺ─˘s final vote by increasing the number of exhausted vote . This could affect the outcome in seats like Noosa, Burleigh, Broadwater, Thuringowa and possibly Kawana where the Greens did not run last time (if they run this time).

Correcting the pendulum results in the trigger figure falling as follows for Labor to lose 22 seats:
  • ECQ two party preferred figure: 9.5%
  • Margins calculated as % of formal vote: 8.2%
  • Elimination of Lib/Nat contests: 8.2%
  • 5% shift from One Nation to Nats: 7.6%

Two party preferred

% Swing of formal vote

No three cornered contests

5% shift from ONP to Nats

1. Noosa  0.9%




2. Burleigh 1.7%




3. Burnett 1.7%




4. Toowoomba Nth 1.8%




5. Clayfield 2.0%




6. Charters Towers 2.2%




7. Broadwater 2.4%




8. Kawana 2.6%




9. Indooroopilly 2.9%




10. Thuringowa 3.5% (I)




11. Aspley




12. Burdekin 5.1%


-5.7% (ON)


13. Mudgeeraba 6.7%




14. Redlands 6.8%




15. Ipswich West 7.2% (ON)


4.9% (ON)


16. Barron River 7.2% (I)




17. Gaven 7.5%




18. Hervey Bay 7.6% (ON)


0.5% (ON)


19. Mansfield 8.6%




20. Mt Ommanney 8.7% (I)




21. Townsville 9.3%




22. Glasshouse 9.5%




23. Whitsunday 9.5%




24. Springwood 10.3%




25. Southport 10.8%




26. Mundingburra 11.4%




- First figure: Two party preferred vote as calculated by the ECQ
- Second figure: Vote changes needed calculated as percentage of formal vote
- Effect of single ONP/CCA or Lib/Nat candidate also indicated, as well as impact of 5% swing from ONP to Nats. (Negative figure assumes Non-government majority. Second candidate assumed to be Coalition unless specified).
- Labor would need to lose 22 seats to lose its majority.


ABC election analyst Antony Green responds to John Cherry and provides his own revised electoral pendulum:

I was interested to read John Cherry's comments yesterday on the swing need for Peter Beattie to be defeated at the February 7 election. After the slagging off I received from Crikey the other day, I though a suitable peace offering might be the little contribution below on optional preferential voting and my own alternative electoral pendulum for Queensland.

It is without doubt that Labor received a substantial advantage in 2001 from the operation of Optional Preferential Voting (OPV). As John pointed out, the result in Burdekin was truly remarkable. Labor polled 36.7% of the primary vote, the three conservative candidates 63.3% between them, but after the distribution of preferences, Labor won thanks to the high number of exhausted preferences.

Equally remarkable was Hinchinbrook. After the full distribution of preferences, 7,192 votes elected the National Party's Marcus Rowell, 6,436 chose the One Nation candidate, and 6,713 votes had exhausted all preferences. 33% of all votes ended up expressing no preference for either of the two remaining candidates. I think we can call this the 'none of the above' vote.

For the technically minded, you calculate a percentage by dividing the numerator by the denominator and multiplying by 100. The numerator is either the primary or 2-candidate votes, while the denominator is the formal votes under compulsory preferential voting (CPV) or the votes remaining in the count under OPV.
Under CPV, your percentage goes up only when preferences are received, the denominator being fixed at all times. Under OPV, your percentage also goes up when preferences exhaust, as the denominator is cut by each exhausted vote. But the key point is, the percentage vote of all candidates does not go up equally. The percentage of the candidate with the highest primary vote always goes up fastest with each exhausted vote. This is why Labor won seats like Burdekin. 58% of preferences exhausted, and as Labor had the highest primary vote, its vote was weighted upward.

So can we come up with a measure that removes the exhausted vote effect. This is effectively to come up with a measure as to what would have occurred under CPV rather than OPV. The assumption I make is to take all the votes that did not have preferences, and distribute them to the two final candidate in the same proportion as the votes that did have preferences. I think this is a reasonable approach to take, and is certainly the most defensible assumption when there is in fact no empirical data to indicate why people exhaust their votes.

Applying this assumption and calculating the percentages, the differences between OPV percentage and the CPV estimated percentage can be seen as the advantage gained  by exhausted preferences.

As an example, a hypothetical election of 1,000 votes as follows.

A - 450 (45.0%) / B - 400 (40.0%) / C- 150 (15.0%)
Say of candidate C's votes, 10 had preferences for A, 40 for B and 100 votes exhausted. Before we go and distribute the preferences, first exclude the 100 exhausted votes and re-calculate the percentages.

A - 450 (50%) / B - 400 (44.4%) / C - 50 (5.6%)
So you see, A's vote went up 5% (and achieved a majority without receiving any preferences), while B's rose 4.4%. The percentage of the candidate with the highest primary count is always boosted in this way. The leading candidate on primary votes is always advantage by OPV. (That is unless the majority of exhausted preferences would otherwise have come to them). The final distribution of preferences then gives

A - 460 (51.1%) / B - 440 (48.9%)
Now, what if all C's votes had expressed preferences in the same proportion to those votes that did. Of the 50 votes with preferences, 10 (20%) had preferences for A. So 20% of all 150 votes is 30, and by the same reasoning, 120 for B. My CPV estimate for this election would now be

A - 480 (48.0%) / B - 520 (52.0%)
A very different result. Under OPV, candidate A ended up with 51.1%, under my CPV estimate, only 48.0%. If I subtract the estimate from the actual percentage, you get a measure of advantage received from the operation of OPV, in this case +3.9%.

Now I have done this for all Queensland electorates. Below is the same table of marginal seats as used by John Cherry. The number on the left is the ordering on the conventional pendulum. I have re-ordered the seats according to my CPV estimate, and included an advantage column.


Two party preferred

OPV % Margin

CPV % Margin

Advantage to Labor

12. Burdekin




10. Thuringowa (v Ind)




6. Charters Towers




2. Burleigh




18. Hervey Bay (v ONP)




1. Noosa




4. Toowoomba North




3. Burnett




5. Clayfield




7. Broadwater




16. Barron River (v Ind)




8. Kawana




15. Ipswich West (v ONP)




9. Indooroopilly




14. Redlands




22. Glasshouse




23. Whitsunday




11. Aspley




24. Springwood




13. Mudgeeraba




20. Mt Ommanney (v Ind)




17. Gaven




19. Mansfield




26. Mundingburra




25. Southport




21. Townsville




As you can see, the seats of Burdekin, Thuringowa, Charters Towers and possibly Burleigh, are in Labor hands in large part because of optional preferential voting. On this pendulum, the swing for Labor to lose 22 seats and its majority comes down to 6.8%, and quite a few seats that are currently on margins above 4% suddenly look much more marginal.

One thing to be careful of though is to assume too much of the victory in 2001 was just optional preferential voting. Sure, Burdekin was a freak result. The same almost occurred in Gympie much to Labor's amazement. But the seat of Burnett is not that dissimilar to Burdekin, another mid-north coast sugar seat. Burnett only had two candidates, so no problem with competing conservative candidate. Labor romped home to win for the first time since 1909 with an 11% swing.

There were 16 seats in 2001 where my advantage/disadvantage measure was greater than 4%. All were seats with competing conservative candidates. Given a choice with optional preferential voting, voters expressed a primary vote intention, but then did not give preferences. If there had been only two candidates, those same voters would have had no other option except abstention, voting informal or choosing between Labor and a single conservative candidate. The evidence from Burnett is that voters may have been prepared to vote Labor so strong was their anger. At this election, without competing conservative candidates, it is hard to see some of the 2001 results being repeated.

Another warning to take from the above table is in the entry for Indooroopilly. Labor was disadvantaged there. While Labor led on the primary votes, it's majority was then built on Green and Democrat preferences. Overall Labor won 62.4% of preferences from votes with preferences, but just over a third of all distributed votes exhausted. If the Greens do well at this election, and their is a high exhausted rate, then Labor could be the party that suffers from OPV instead of the the Coalition.

After all, that was one of the problems for Wayne Goss in 1995. Labor would probably not have had its problems in Mundingburra at that election, or lost Mulgrave, if the government had not so alienated Green voters.

Senator Cherry responds to Greenĺ─˘s argument:

ĺ─˙Antony Green's 'revised' electoral pendulum highlights the real advantage that the optional preferential voting system had for Labor in 2001 with One Nation cannabalising the Coalition vote.

But, it also highlights the risks for Labor in 2004 with One Nation's vote in decline and the Greens now contesting upwards of 70 seats, twice the number in 2004.

Simply put, and despite all the rhetoric about Greens preference deals in today's papers, Green voters are incredibly ill-disciplined when it comes to preference allocations.

In 2001, the Greens directed preferences to Labor in every marginal seat in Queensland bar two (Greenslopes and Indooroopilly). Yet, in the six most marginal seats won by Labor which the Greens contested (Clayfield, Barron River, Glasshouse, Indooroopilly, Gaven, Mudgerraba and Mt
Ommanney), 65% of Green voters ignored the Greens how to vote card and only 35% gave their preferences to Labor - 47% allocated no preferences and 18% gave preferences to the Coalition or others.

Ironically, in Indooroopilly where the Greens didn't allocate preferences, the flow to Labor was stronger (52%) and the exhaust rate was lower (28%) than the seats where they did.

Thus the decision by the Greens to double the number of candidates they contest is likely to cost Labor around 2-3% of the two party preferred vote in every seat the Greens contest even if the Greens decide (as they usually do) to direct preferences to Labor. On the other hand, their poll results (4% in the latest Morgan and Newpoll) suggest that the Green vote is not that much moved from the 2001 result.

Labor is still deciding whether to run its 'just vote one' campaign again at this election. But it is likely that regardless of the campaign, many Queensland voters will again decide to exhaust their preferences, which could hurt Labor more than the Coalition in this election.ĺ─¨

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