How did the polls do (provisional outcome)?

Provisional results are in. Here’s how the polls have done so far.

chart (5)

You can find the detailed comparisons in this Google doc. Here are a few notes:

  1. In 2014 the official results changed things quite a lot. I’ll post an update when they’re out in a couple of weeks.
  2. Well done Reid Research – outstanding job and huge improvement over 2014. 
  3. At this point, the Herald Election forecast has done the best of all the forecasts and polls-of-polls. They’re at least as accurate as the Colmar Brunton poll.
  4. Roy Morgan (the only poll to call cell phones) has not done so well this time, but they did not release a pre-election poll. Unlike the other public pollsters (who have developed bespoke election poll methodologies) Roy Morgan include their preference question in an omnibus survey which runs to a fixed schedule – their poll finished in field on 10 September.
  5. There is still no “polling crisis” in New Zealand. The established polls have done pretty well, once again.

Unfortunately, with only three public polls left in New Zealand, the forecasts and polls-of-polls don’t have much data to inform their models and calculations. It can’t help either that polling methods change, making house effects unstable over multiple elections.

While they don’t perform as well as the actual polls at predicting the election result, the forecasts and polls-of-polls are really useful for reducing the noise, and understanding if voter sentiment is changing over time.

UPDATE: DPF shared the pre-election results for some other polls I wasn’t unaware of, so I’ve added these.


7 thoughts on “How did the polls do (provisional outcome)?

  1. Good coverage. It would be useful for the research companies to get together and examine their respective results – I think the one poll that possibly jumped sideways was the CB poll that had Labour ahead. It would be very interesting to see if UMR recorded a similar spike.

  2. I’m still struggling to understand what these polls attempt to achieve. I’m a thinking adult who casts a vote based on the soundness of policy and the integrity of the individuals/parties promoting that policy. Why do I need to know what 1,000 other people are thinking? (+ or – 3% margin of error!!!). I can understand how the media relishes such pumped up sensationalism to bring the reader/viewer closer to the advertiser, but (unlike weather forecasting) I can’t see what useful purpose these polls serve. If anything, I believe they are self-serving, unnecessary noise that hampers (not enhances) the democratic process. As such, I would be a proponent for banning the publication of such polls for a determined time period before an election.

    1. Hi Mark

      Public polls play an important role in a democracy. Imagine if the media weren’t able to report on what the general public support or oppose? How would we know whether to believe what the politicians or other prominent figures tell us?


      1. I am not suggesting the media NOT report what what the general public support or oppose. I understand the metrics, but how one extrapolates a survey of 1,000 people (+ or – 3% margin of error) as the “general public” is being slightly liberal in one’s interpretation. Let’s be honest, opinion polls are a comparatively cheap way for the media to pack a punch and deliver headlines. Who wants to fill their newspapers, TV screens or websites with thousands of letters to the editor to broadcast what people really feel. That would take up too much advertising space! At a time when we are about to make a decision on who and what policies are going to govern our lives and the outcomes of our country for the next three years, I fail to see how corralling those decisions by polling (only to generate advertising revenue) can be constructive.

    1. Your ultimate sentence is correct, and indeed my point. How often polls get it right/wrong is often akin to the performance of my TAB account 😉

  3. And please do not get me wrong. I see many uses for opinion polls. But the motive behind them and the quality of decision making they supposedly facilitate in the run up to a general election is very questionable in my view.

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