July 31, 2020

Bogus polls

The recent trends in opinion-poll support for the National Party got a lot of attention. That’s because real opinion polls, like those done by Colmar Brunton and Reid Research (and the internal party polling that they tell us about when they think it will help them) are genuine attempts to estimate popular opinion.  You can argue about how good they are — but you can argue about how good they are, there are factual grounds for discussion.

NewsHub ran a bogus online clicky poll with the question Who would you prefer as Prime Minister – Judith Collins or Jacinda Ardern?  Of the people who clicked on the poll, 53% preferred Ms Collins, and 47% preferred Ms Ardern.  Let’s compare that to the two real polls. The 1News/Colmar Brunton poll had

  • Jacinda Ardern: 54% 
  • Judith Collins: 20%

The 3/Reid poll had

  • Jacinda Ardern: 62% 
  • Judith Collins: 15% 

Why are these so different from the Newshub clicky poll? The first point is that there’s no reason for them to be similar. Two of them are estimates of popular opinion; the other one is a video game.

On top of that, the question is different.  The real polls are asking who (out of basically anyone) is your preferred PM.  The bogus poll forces the choice down to Ardern vs Collins.  If you supported Simon Bridges or Todd Muller — or Metiria Turei  or Winston Peters — the real polls let you say so, and the bogus poll doesn’t.

Research Association NZ, who are the professional association for opinion researchers in NZ, have a code of practice for political polling (PDF). It’s only binding on their members, but it does have best practice advice for the media, such as using the term “poll” only for serious attempts to estimate public opinion, not for bogus clicky website things.

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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 See all posts by Thomas Lumley »

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