March 29, 2017

Technological progress in NZ polling

From a long story at

For the first time ever, Newshub and Reid Research will conduct 25 percent of its polling via the internet. The remaining 75 percent of polling will continue to be collected via landline phone calls, with its sampling size of 1000 respondents and its margin of error of 3.1 percent remaining unchanged. The addition of internet polling—aided by Trace Research and its director Andrew Zhu—will aim to enhance access to 18-35-year-olds, as well as better reflect the declining use of landlines in New Zealand.

This is probably a good thing, not just because it’s getting harder to sample people. Relying on landlines leads people who don’t understand polling to assume that, say, the Greens will do much better in the election than in the polls because their voters are younger. And they don’t.

The downside of polling over the internet is it’s much harder to tell from outside if someone is doing a reasonable job of it. From the position of a Newshub viewer, it may be hard even to distinguish bogus online clicky polls from serious internet-based opinion research. So it’s important that Trace Research gets this right, and that Newshub is careful about describing different sorts of internet surveys.

As Patrick Gower says in the story

“The interpretation of data by the media is crucial. You can have this methodology that we’re using and have it be bang on and perfect, but I could be too loose with the way I analyse and present that data, and all that hard work can be undone by that. So in the end, it comes down to me and the other people who present it.”

It does. And it’s encouraging to see that stated explicitly.


Thomas Lumley (@tslumley) is Professor of Biostatistics at the University of Auckland. His research interests include semiparametric models, survey sampling, statistical computing, foundations of statistics, and whatever methodological problems his medical collaborators come up with. He also blogs at Biased and Inefficient

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  • avatar
    Peter Davis

    This is a real worry. Paddy Gower has to be one of the most slipshod journos I have come across. There is a lot of competition for this title, including Garner. So, there is no way Gower is going to show any restraint in interpreting results, if they look newsworthy. But, on top of that, is there a reputable provider of these services in NZ and do they have a track record for providing valid results? I think not!

    9 months ago

  • avatar
    steve curtis

    Paddy said in the article
    “We just thought that polling was too important to stand still and keep doing things the way we were always doing it,” says Newshub political editor Patrick Gower, who was heavily involved in the shaping of the new polling system. ”
    Im curious what his expertise in shaping the polling techniques were ?

    9 months ago

  • avatar
    Leon Iusitini

    Do Reid Research and the other main polling companies weight their results by probability of turnout? (or use some other method for correcting for differences in likelihood of actually voting)….

    9 months ago

    • avatar
      Thomas Lumley

      Yes, I believe they all have some sort of likely-voter thing.

      9 months ago