Pollsters, prophets and politics: On the ball or off the mark?

Analysis - "Bugger the pollsters," Jim Bolger said on election night in 1993, when his eventual victory turned out less comfortable than predicted.

One imagines the phrase - or one similar - was bandied about plenty in 2016.

The polling industry's reputation has taking a drubbing after several major misses abroad last year, most notably Donald Trump's shock victory in the US Presidential election.

But here in New Zealand, pollsters continue to have confidence in their art.

Stephen Mills is executive director of UMR Research - the chief polling agency for the Labour Party.

He said it was "absolute hysterical stuff" for some commentators to suggest "we'd be better to go back to checking entrails".

Polls have performed well in recent NZ campaigns and in the lead-up to last year's Australian election, he said.

"Every public poll was pretty much spot on and there was no mass publicity sweeping around the world - pollsters have really got it right!

"In Australia and New Zealand, unless and until there is a systemic failure, we can be... reasonably confident."

The American Association for Public Opinion Research (AAPOR) has been analysing how almost every major poll missed Mr Trump's presidential triumph and will report back by May 2017.

Overall, the national polls were mostly accurate in picking Hillary Clinton to win the popular vote - which she did by nearly 3 million votes.

The state polls in the so-called Rust Belt, however, were significantly off and the much-celebrated polling aggregators such as FiveThirtyEight and Upshot were wrong too.

Mr Mills said it looked like the sector had talked to the wrong types of people.

"What I think they've done is used historical models. And they've underestimated ... the turnout amongst the rural, poorly educated white voters [in the Rust Belt].

"There's also the theory of shy Trump voters. They won't admit to a pollster they're going to vote for him or won't even communicate with a pollster. They just hang up or tell them to bugger off."

Mr Mills' right-wing counterpart is David Farrar. He heads the polling company Curia, which is National's pollster.

He said the polls were very accurate in New Zealand's last election, but "it's the ones that the polls get wrong that of course stick in memory".

Mr Farrar said New Zealand's MMP system could give people more confidence in surveys here than in the US.

"If the election result is 2 percent different to the polls, that's a two seat difference to that party. Under First Past the Post (FPP) in the UK, that could be a 30 seat difference."

Both Mr Mills and Mr Farrar were waiting to see the US inquiry's findings, but neither planned to make drastic changes to their practices just yet.

Mr Farrar said Curia did check its samples and weightings, but there was only so much they could do.

"If you try and weight on everything, you'll have to phone 10,000 people till you find the left-handed Catholic bachelor's student from Waiheke Island!"

Freshly-departed prime minister John Key was known to follow opinion polls almost religiously. In his 2014 victory speech, he admitted to having phoned Mr Farrar "night after night" in the lead-up to voting day.

"The level of interest the former Prime Minister took in the polls made Gollum look like a quitter when it came to the ring," said Mr Farrar.

When quizzed this week, Mr Key's successor Bill English claimed a more circumspect approach, saying he viewed polls as just "one indicator".

"I don't spend a whole lot of time on the details of how polls work," he said.

Political analyst, Colin James, curates a Poll of Polls for RNZ.

It tracks an average of the four most recent major polls from among ONE News Colmar Brunton, Newshub Reid Research and Roy Morgan, as well as the unpublished UMR Research and Curia.

"If you take a trend line through the average - say the last three months leading up to an election - and you project that trend line ahead to the election day, it comes out very close to the final result," Mr James said.