October 22, 2017

Bogus-poll headlines

The headline:

Kiwis want cannabis legalised – Herald Facebook poll

And in the text

An unscientific poll run on the NZ Herald Facebook page shows that the majority of New Zealanders want to see cannabis legalised.

The poll doesn’t show anything of the sort, because bogus polls can’t show anything of the sort.

According to the story there were about 15,500 ‘yes’ responses. A bogus poll doesn’t tell you anything about people who didn’t participate. Even if we knew these were different people and all New Zealanders, it would still be just under half a percent of, say, enrolled voters.

It was just a few months ago that Nicholas Jones in the Herald reported a real poll, which asked a more detailed set of questions and tried to sample a representative group of people.  That adds information to the debate. Headlines based on bogus polls subtract information.

avatar

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 »

Comments

  • avatar
    Steve Curtis

    Even the real poll gives choices which are ‘blurry’, those being legalised, decriminalised and illegal.
    A sample question – possession of small amount for personal use- still only gets 28% for a change in the current situation to being legalised.
    Funny, that sort of result doesnt get into the headlines

    4 weeks ago

    • avatar
      Thomas Lumley

      One of the good things about the poll is that it *does* show the blurriness in public opinion: eg only 31% think possession of a small amount for personal use should be illegal but 41% think growing for personal use should be illegal and a majority think buying it or growing it to distribute should be illegal.

      So, yes, there’s a lot more support for legal use of cannabis than for any legal way to obtain it.

      4 weeks ago

  • avatar
    Antonio Rinaldi

    I trust this poll. It’s because people want to have more sex, and it has been proved that people smoking cannabis have more sex:
    https://www.theguardian.com/science/2017/oct/28/high-libido-cannabis-smokers-have-20-more-sex-researchers-find
    (smile)

    3 weeks ago