The Dim-Post

March 26, 2015

Chart of the day, second thoughts edition

Filed under: Uncategorized — danylmc @ 9:50 am

Here’s the tracking poll updated for the first time since the election.


  • I’ve switched off bias-correction because it wasn’t a very good predictor of the actual outcome in 2014.
  • Labour have almost won back the support they lost by putting Cunliffe in charge
  • New Zealand First outperformed the polls during the last two general elections. The theory is that his demographic of older voters votes in a greater proportion than the general population.
  • What does that mean for Northland? Possibly nothing because the majority of people voting for him won’t be traditional New Zealand First voters. But it makes me less certain of a National win. They’re a long way behind in the polls and people who vote for Peters do turn out. I’m a lot less certain.


  1. I don’t think high voting levels among seniors is a theory, it’s a pretty well established fact confirmed by almost every piece of research performed since at least the 1970s.

    The question is, why would Winston’s high support among a high-voting member of the public not show up in a poll? Do polls not pick up seniors for some reason?

    Comment by kalvarnsen — March 26, 2015 @ 10:11 am

  2. Polls don’t pick up seniors due to the fact they are land line based and don’t incorporate telegram, semaphore and carrier pigeon. It’s why all polls are massively biased

    Comment by King Kong — March 26, 2015 @ 10:21 am

  3. Don’t pollsters usually weight for demographic turnout, ie compensate for the known fact that older people are more likely to vote? Alternatively, doesn’t the restriction to “likely voters” inherently compensate for that? I’m waiting for that nice dude who actually does polls to show up and tell us.

    Comment by Stephen J — March 26, 2015 @ 10:28 am

  4. I’ve tried to reply a few times sorry, but something in my message is causing it to be blocked by WordPress.

    Comment by Andrew — March 26, 2015 @ 12:11 pm

  5. I’d say that it’s a bit like how polls about what magazines you read tend to not match sales data on the mags, because people are embarrassed about some choices and don’t want to say it out loud to a pollster. Peters is a bit like a voting for Penthouse.

    Comment by Ben Wilson — March 26, 2015 @ 1:54 pm

  6. @kalvarnsen: Polls do pick up seniors. But if seniors are more likely to turn out to vote than other demographic groups, and more likely to vote NZF, then the poll will underestimate the support for NZF. (Even if the polled sample includes a proportion of seniors that is similar to that in the general population).

    @Stephen J: I’m not a pollster, but I don’t believe that the pollsters usually weight for differences in turnout across demographic groups. Depending on the poll, they may use demographic weighting, but in the more limited sense of adjusting for demographic differences between the sample and the general population. That said, the polls do quite often ask respondents how likely they are to vote, and may exclude those who say they are unlikely to vote (depending on the survey).

    Comment by Matt — March 26, 2015 @ 2:11 pm

  7. I thought most polls did some sort of weighting for which demographics are more likely to vote. Roy Morgan notably doesn’t.
    However, the likelihood of a person in a particular demographic voting could vary depending on which party they support. For example, maybe old people who vote New Zealand First are just as likely to vote as any other old people, but young people who tend towards New Zealand First have this same high rate of voting as other NZF supporters, rather than sharing the same lower rate of voting as other people their age. A poll that weighted for chance of voting based on age would not pick up on that, thus underestimating New Zealand First’s vote.

    Comment by Can of Worms, Opened — March 26, 2015 @ 4:00 pm

  8. Ben, in the last few hours I’ve seen you write some cracking good tweets on #MCGsobig and now you’ve compared Winston Peters to Penthouse – well done that man!

    Comment by Phil — March 26, 2015 @ 5:20 pm

  9. @Matt: Yeah, what others have said. Polls have been weighting for likely voters since the 80s.

    I think the real reason for Winston’s underperformance is that a relatively small but consistent chunk of his supporters are ashamed to admit they’re going to vote for him, even in the context of a confidential anonymous poll.

    Comment by kalvarnsen — March 26, 2015 @ 6:46 pm

  10. @Phil 🙂 I’m saving up the best Chuck Norris recyclables for Winston. The National rattesnake bit Winston. After 4 agonizing weeks, the snake died….

    Comment by Ben Wilson — March 27, 2015 @ 10:22 am

  11. New Zealand First outperformed the polls during the last two general elections. The theory is that his demographic of older voters votes in a greater proportion than the general population.

    If that’s true, [it is], then the polls would correct for it, so it’s not the explanation.

    Comment by Graeme Edgeler — March 27, 2015 @ 7:55 pm

  12. @GE –

    1) Winston is a master political operative. He has a track-record of nailing a hot-button issue at the last minute and tapping into the fears and prejudices of just enough voters at just the right time in the campaign cycle.
    2) Polls lag at least a week or so.
    3) A lot of voters don’t make their mind up until the minute they reach the polling booth.

    If you accept those three things are probably true, then there is no mystery at all in NZF’s performance.

    Comment by Phil — March 30, 2015 @ 8:32 am

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