January 20, 2012

Bogus smoking poll.

From the NZ Herald

Auckland councillors are divided over a proposed smoking ban in public outdoor areas, but the majority of New Zealanders say the idea is either sensible or good in theory.

If you read the article, it turns out that the claim about the majority of New Zealanders is based on the clicky poll on the Herald website.  That is, the data come from what the newspapers ordinarily call “an unscientific poll”, and we at StatsChat prefer to call “a bogus poll“.   Last week I criticised the Drug Foundation online poll results as ‘dodgy numbers’.  This is well beyond ‘dodgy’.

In the Drug Foundation poll, the point was that a non-negligible fraction of people believed drug driving was safe, and the poll provided at least some support for the argument even if the numbers were unreliable.  And the Drug Foundation collected a lot of demographic information so it was possible to say something about the ways in which the sample was biased.

In this example it really matters whether the support is, say , 40% or 70%, and we have no idea of the extent of the bias, except that there are probably responses from people outside Auckland.

If a ban on smoking in public outdoor areas had sufficiently strong majority support (perhaps 2/3 majority), I wouldn’t necessarily be against it, but we need real numbers, based on real opinions of a concrete plan.

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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
    Murray Jorgensen

    One thing that I believe may be acting in polls of this kind, whether well designed or bogus, is the presence of “stigma”. People like to be thought to be for “good” and against “evil”. This would apply particularly when a newspaper is going to publish a little mug-shot of you beside your opinion. Smoking carries a stigma in our society and people are likely to endorse further restrictions on it whatever their true beliefs are.

    Disclosure: people have been known to smoke in the lane outside a bar I have an interest in.

    12 years ago