Political polls aren't cheap to produce or purchase, so they'll only be commissioned by organisations that derive actual value from them. In the case of so-called internal polls by political parties, the value lies in knowing where you are, not just overall, but with respect to specific demograhics and specific policy or political questions. Sometimes you'll want this literally on an overnight basis.
For media organisations, the motivation is slightly different. Commissioned polls are news you can can own. They are exclusive at the time of publication and if they're sufficiently interesting they may then be picked up and quoted by other media organisations. The natural approach to maximising the value of your investment in a poll is to make a compelling story of it -- to make it look at much like news as possible. The one thing you want to avoid on your own poll day is acknowledging there are any other polls in existence.
Thus, 3 News understandably reported its Reid poll last night as a calamity for Labour and its leader, who have both slipped in popularity relative to the last 3 News Reid poll. It's certainly not great news for them. But on the same page is a link to a report on recent a Roy Morgan poll, which has Labour and National on virtually same ratings as the new Reid poll (just over 31% and 45% respectively). That newsbrief is headed 'NZ election too close to call'.
Last night's assumptions on the appearance of a virtual Parliament (were an election held today, etc.) were governed by an essentially meaningless shortfall of 0.1% which, according to this poll, would see New Zealand First fail to make the 5% threshold. The more realistic assumption would be that a lot is going to ride on what New Zealand First does this year.
Which is precisely the angle of One News's report on its own Colmar Brunton poll, also last night. And while Patrick Gower told his viewers that National's Oravida troubles hadn't hurt it all, Corin Dann told his viewers National had "taken a hit" over Oravida, sliding four points to 47% support (that is, two points higher than the Reid poll).
There are less obvious but interesting elements in each poll. Green Party co-leader Russel Norman was quick to note on Twitter last night that compared to the Reid 3 News poll at about the same time three years ago, National was down nine points and the Greens up three. It doesn't prove much beyond the fact that individual polls months out from a general election can bear little resemblance to the eventual election result, but that's a fact worth bearing in mind.
One interesting nugget in the full Colmar Brunton results is the proportion of undecided or refuse-to-say voters (who are excluded from the headline figures)-- 18%, up five points on the previous poll. That didn't feature in the report, but it seems a notable shift. On the preferred Prime Minister question, "don't know" was 30% -- the same as the last poll, but up six points on last May. That could signify a number of things.
This isn't a whine about how the polls are unfair to the left because landlines or whatever. The party and its leader David Cunliffe are going in the opposite direction to what they'd want. But the big danger for Labour in particular lies in the creation of a news narrative that will deter some potential voters (because there's no point) when in fact the the question of who gets to form a government in September is not at all a done deal.
Some of the best commentary comes from Danyl, who has updated his poll of polls and notes that with the Conservative Party tracking at 2.9%, National has a tricky decision to make about extending a helping hand to the Conservative Party. Lose a sympathetic vote bloc if the Conservatives can't crest 5%? Or throw Colin Craig an electorate seat "and lose some voters to the Conservatives and a whole lot of center-voters might panic and switch to Labour, New Zealand First or the Greens."
There's one more wrinkle. 3 News was lauding new Act leader Jamie Whyte for lifting his party from zero (clearly not the party's real level of support) to 1.1% -- and highlighting the Internet Party's debut on 0.4%. But One News has Act on o.3%, its lowest rating since October last year, and "others" on 0.4%.
So: unappetising results for Labour and its leader. But it's a little too soon to be sketching out seats in the House.
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If you haven't already, it's worth reading UMR's Gavin White in the historical accuracy of the major political polls. He finds that polls consistently overstated National's support when compared to actual voting at the last election and going back to 2005, and did so to a lesser degree for the Greens. Labour's vote was slightly overestimated in 2011 and slightly underestimated going back to 2005. For National, consistently looking two and a half points more like winning may have been a non-trivial electoral advantage in itself.