Pollsters comment on vastly different poll results

I think there has been much ado about a couple of poll results, with much more made of the results than they deserve, The polls are of interest but not of great importance in the whole scheme of things.

But it’s worth listening to what the polling companies think.

The Spinoff – Two polls. Two wildly differing results. What happened?

Last night’s polling results had little in common, with the only consistency across both being that Simon Bridges is a very unpopular party leader. In short: the Colmar Brunton poll showed National up to 44%, and Labour dropping to 42%. It showed Jacinda Ardern as preferred prime minister for 45%. The Newshub Reid poll showed National at 37.4%, and Labour at 50.8%. It showed Ardern as preferred PM for 49%.

The Colmar Brunton explanation:

…the divergence doesn’t necessarily mean one is wrong. “Without digging into what Reid’s methodology is and what the details are it’s hard to comment on why there’s a difference,” said Jason Shoebridge, CEO of Kantar, Colmar Brunton’s parent company.

I asked him why he thought there was a difference in the results, and it turns out there’s a simple explanation: “Reid use an online methodology as well as landlines, and we just use landlines and mobile phones. Then there’s a difference of when we were collecting the data – we were collecting later than they were.” Colmar Brunton was conducting their research from the 4th to the 8th June, and Newshub-Reid Research did theirs from the 29th May to the 7th June.

The last Colmar Brunton poll was taken in the days following the Christchurch terror attacks on March 15th, an event for which Ardern was near-universally praised for her handling, so it’s not surprising to see Labour’s popularity declining closer to what it was before the attack. With this in mind, alongside the recent furore around the wellbeing budget, Ardern’s result in both polls could be seen as a win.

One way to tell the accuracy of a poll is how it fits into the over-arching trends, and in general, polls prior to this showed Labour going up and National going down. Shoebridge believes the only true measure of a poll’s accuracy is an election.

that should be impressed on the media who promote their polls as major news.

“Where the stress really comes in is on election night – that’s the real test,” he explained. Political opinion polling is the most high profile work the company does, even though it’s only a small proportion of their business. “We always want it to be as accurate as possible, and we’re confident in our numbers.”

Reid Research was confident but offered no explanation.

Reid Research was not at liberty to release more information to us due to its commercial relationship with Newshub, but said it was confident its poll was correct.

A poll with a small sample cannot be ‘correct’. The only correct polls are elections. Everything else is an approximation with well known margins of error and possibilities of greater errors.

It is almost certain that if another poll was taken this week it would have a different result.