Victoria 2018 – the early vote gap

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I thought I would dive into some of the interesting data trends from last weekend’s Victorian state election, since fellow bloggers William Bowe and Kevin Bonham are doing a great job tracking the close races as counting continues.

I’ve been interested in looking at how the pattern of results differed between election day votes and pre-poll votes (otherwise known as early votes), in particular how the smaller swings in the special votes pulled back the predicted Labor seat gains on election night.

We don’t have a final turnout figure, with quite a few votes left to count, but the proportions suggest that the total pre-poll vote could end up being close to one third of the entire statewide vote, compared to 25.8% of the total vote in 2014.

Vote type20142018
Election day2,071,4971,713,471
Pre-poll912,967906,727
Postal294,571174,973
Absent220,44811
Provisional37,6220
Marked as voted990

2018 voting figures as of Wednesday evening, 28 November

For the rest of this blog post, I’m using data I downloaded on Tuesday morning for the 77 seats which have a Labor vs Coalition two-candidate-preferred count (and thus are possible to use to calculate a comparable swing from 2014).

The 2PP swing to Labor on election day was 5.8%, compared to only 2.8% for pre-poll votes, and 2.8% for postal votes.

The difference in swing is relatively consistent between different seats, with an 80% correlation between the Labor swing in the pre-poll and election day vote. You can see this trend in the following graph:

If the two swings were similar in scale you’d expect the trend line to go up at a 45-degree angle – the shallower slope confirms that the early vote swing tended to be smaller than the election day swing.

I originally produced a map which showed how much larger the swing to Labor was on election day as a percentage, but since there is a close relationship between the different vote type swings, this would mostly just show you where the swing was big.

So instead I calculated a ratio between the Labor swing on election day, and the Labor swing in the pre-poll vote. Those places with a higher ratio had an election day swing that was much larger than the pre-poll swing. Rowville had a ratio of 11.6, due to a swing on election day of 5%, and a tiny 0.4% swing in the pre-poll vote. No other seat has a ratio of more than five. Only eight out of 77 seats analysed have a larger pre-poll swing than on election day.

Looking at this map, you can see why there were problems projecting some of those traditional Liberal seats like Sandringham, Brighton, Caulfield and Hawthorn on election night. All of these seats had very large differences between the election day and pre-poll swing.

On the other hand, more typical swing seats like Mordialloc and Carrum had larger pre-poll swings than on election day, while Bentleigh and Frankston had very similar swings between different types of votes.

It’s worth noting that we saw a similar trend in the Wentworth by-election as we did in the inner south-east Liberal seats last Saturday, with the Liberal vote holding up much better than expected on the pre-poll vote.

While this may reflect separate campaign effects in both elections producing a last-minute surge, I do also wonder if we are seeing more of a difference between the kind of person who votes early and who votes on election day in these particular seats. As the pre-poll vote grows fast we can’t assume the partisan mix of these voters won’t change, so past election results may not give us a great sense of how these people as a group may vote relative to the entire electorate.

As the pre-poll vote continues to grow, now potentially making up one third of the entire electorate in Victoria, we’re going to need better methods of being able to project this vote.

At federal elections, each pre-poll booth is treated as an independent booth to be counted on the night, just like all of the election-day booths (pre-poll votes cast outside of the voter’s electorate are lumped in as a single total, but the same is true for election day votes cast outside of the voter’s electorate), which should make it easier to analyse pre-poll votes.

It’s concerning that the Victorian Electoral Commission, like a number of other state electoral commissions, continues to lump in this massive pool of voters into a single category in the voting figures.

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25 COMMENTS

  1. This is an interesting issue, but not sure I follow the analysis. With election-day swing on the vertical axis of the chart, the shallow slope would actually indicate a lesser election-day swing. However looking at the slope is the wrong approach anyway, as there is clearly an offset – the line-of-best-fit does not go through the origin. Rather, a 0% pre-poll swing begets a 3.8% election-day swing and the election-day swing grows at a further 0.68% per 1% of pre-poll swing (less than 1-for-1, hence the shallow line).

    Given this offset, I don’t think it makes much sense to look at the ratio of the swings. Differences that are on the trendline will generate different ratios depending on where on the line they are – Rowville is only a little above the trendline but gets a big ratio due to a small denominator. I think either absolute differences or variances to trend would offer more insights.

    One thing I note is that the low-swing Nationals seats tended to have a smaller (by magnitude) swing on election day, consistent with the idea of a 3-4% better result for Labor across the board in election day than in pre-poll votes.

    An interesting question is whether the results mean the campaign swung dramatically in the final days (this was the interpretation of a similar result in the Wentworth by-election), or whether the new pre-poll voters are disproportionately Coalition voters. The fact that the safe Nationals seats seats had a better result for Labor (a smaller negative swing) on election day indicates against a third explanation, being that pre-poll voters are less likely to be swing voters.

  2. One note of caution Ben. Your numbers are comparing within district pre-polls for 2018 with all pre-polls in 2014. The trend and variability might not be so pronounced with the final pre-polls.

  3. Not all 2CP counts are accurate- you and VEC have Eltham at -1.15% prepoll 2CP swing despite +8% primary swing. Once recounts are complete, based on other preference flows, corrected swing is looking more like +6.5% 2CP.

  4. Fascinating analysis Ben, great job!!!

    This seems to be a trend where prepoll votes are pulling margins back in favour of the Liberals/LNP – it was the same at the QLD election last year. I think it is just Liberal/LNP voters that just want to go, vote early and get it over with, as they always vote Liberal/LNP. It is the Labor voters (and “swinging” voters) that leave it to election day because they don’t really want to vote (probably wouldn’t with non-compulsory) voting.

    I think this trend has led to over-excitement about swings to Labor on election nights, given margins have come back to the Liberals/LNP with prepoll, though absent votes push the margin back – looks like that is happening in Hawthorn unfortunately. It is being considered that Liberals are losing final weeks of the campaigns but I think it is the Liberals/LNP start strong, whereas the Labor machine builds up and just swamps us…

  5. I just sent a letter to The Age saying that the Liberals should select a capable women like Mary Wooldridge or Georgie Crozier as leader, and it does not matter which house they are in until the next election, as the men for the most part, have not been any good since the excellent Jeff Kennett left in 1999. The media are still talking about men only from the eastern suburbs as usual.

  6. I know this is a small point but I am noticing a number of political watchers are spelling Hawthorn with an “e” and I am not sure why because there is no “e”, we don’t see the Hawthorn Football Club spelt with an “e” and the suburb isn’t either.

  7. Adrian

    Both those women MP’s are in the upper house, so they would have to find their way down to the lower house.

    One women they could go with is Cindy McLeish, she did very well to only suffer a 1.5% swing in her marginal seat of Elidon.

  8. The leader should be in the lower house but with so few Liberals left it does not matter. Perhaps the Liberals should pre-select more women in winnable lower house seats too.

  9. Adrian

    The Liberals will have that chance now they have lost Box Hill, Ringwood and look like losing in Hawthorn and Caulfield with Prahran looking set to remain marginal, this gives the Liberals a chance to run five women candidates in winnable seats and assuming Matthew Guy vacates Bulleen then Wooldridge can move into that seat as she was the one Guy beat for the seat when he moved into the lower house.

  10. I think Caulfield is still OK for the Libs and Prahran OK for the Greens. Check out the VEC website.
    Good point about Bulleen, I was not aware of that about Woodridge and that pre-selection. Blokes win out again in safer seats.

    The 104 Exhibition St HQ is sold so the bunker staff may be homeless on Melbourne streets.

  11. The ABC and other have to refer to the real figures from the VEC I would have thought. The ABC is OK at prediction or calling it early in the evening but the ballot papers are with the VEC and cant be disputed after rechecking.

  12. After all the votes are counted the prediction model says 56 seats for Labor, Thats my final call, Labor almost certain to get Bayswater, and Likely to get Hawthorn and Caulfield. Its sad really that John loses his seat. He would have made a great leader, He is from the moderate faction that actually would appeal to voters, Now your going to end up with O’Brien, He would lose in a Landslide next election because Victorians don’t want a Napthine state style /Morrison Right wing style government. John would need a miracle in Hawthorn, 2022 will be a large Labor win if O’Brien is leader you might doubt this, But i do allot of research into this, And i see it

  13. The Liberals should elect women as State President of the Victorian Division and Parliamentary Leader as the men have been duds (Doyle & Co) since the excellent Jeff Kennett left parliament in 1999. Male staff (since sacked) at 104 Exhibition St were involved in undermining a former Liberal Premier online while a former male State Director was a crook who stole millions of dollars of members funds. Liberal men cant even be trusted to plan a winning election campaign. The recent Labor campaign was faultless by contrast and I am not a Labor supporter.

  14. Why do you support the Liberal party? They are corrupt look at all whats happening right now. Also R.I.P George H.W Bush

  15. The Liberal party need a clean up as Labor did in Victoria in 1992 but it does not mean I am a lackey to any party. The Bush family, and their lackeys like Cheney, Rumsfeld, Powell and Rice, is one of the most evil families in the late 20th and early 21st century. RIP = Rotten Imperialist Pillagers.

  16. I’ve been looking at Caulfield and in that seat the booths with the biggest downturns in on-the-day voting tended to also have the largest 2PP swings to Labor. That’s consistent with Liberal voters voting earlier but obviously Caulfield is a bit of a special case because of its high Jewish vote – might be worth checking some other random seats to see if the same pattern holds.

  17. Both Lib and Lab candidates are Jews. I listened to the ALP candidate on an interview with a Jewish on line TV show and she was unimpressive.

  18. Serious lack of class there Adrian about the Bush family, those words would IMO be much more suited to families like the Kim dynasty and house of Saud.

  19. Mikey of Buninyong – The truth hurts some war monger like Howard, Blair and Co too. Bush Snr was involved in many interference’s in South and Central America and not just the 1st Gulf War. The USA is a declining super power and China and India, trade wise, are the way ahead for Australia.

    I had a letter published in the Canberra Times online a few days ago, check it out, wondering why they trot out John Howard at election time which is pointless and calling John Howard an Iraq war monger.

    I have generally be a Liberal voted but at the next federal election Labour will be ahead of Liberal for the first time since the Whitlam era. That rats nest in Canberra needs to be cleaned out. What does IMO mean?

  20. Daniel – No Trumps friends the Saudis, who the US is still arming to slaughter and starve civilian in Yemen, did it predominately. Well citizens of Saudi Arabia, including some from the Bin laden family, who are mates of the Bushes. US arms in Afghanistan during the Soviet occupation helped empower the insurgents too.

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