Last month Chris Elliot, the Guardian’s readers’ editor, quoted a letter from a reader saying there “seemed to be a cultural problem among Guardian reporters that it is of no consequence if you completely misunderstand or mis-report the figures in a story […] I hope that you can urge on the editor some training of reporters on basic understanding of statistics”. Chris Elliott said he had organised three sessions with external statistical experts for Guardian journalists in the past year (and Nigel Hawkes at Straight Statistics reveals he was one of them).
The Observer’s readers editor should probably do the same. Earlier this month the Guardian’s front page story mentioned an open-access voodoo poll on the Royal Medical Journal’s website that had been touted round Twitter as if it was meaningful. The Observer this weekend was on a similar subject, but was worse – hanging a whole story on very dubious figures.
The story is titled “Nine out of 10 members of Royal College of Physicians oppose NHS bill”, and claims that “a new poll reveals that nine out of ten members of the Royal College of Physicians – hospital doctors – want the NHS shake-up to be scrapped.”
The story is based upon an open access survey created by and linked from a website campaigning against the heath bill, callonyourcollege.blogspot.com, and again, bandied around Twitter. The survey was open access, so there could have been no attempt at proper sampling and contained no demographic information that could have been used to weight it. It should go without saying that a survey from a website campaigning against the NHS reforms and co-ordinating opposition to it amongst the Medical Royal Colleges is more likely to be found and completed by opposed to the bill (in much the same way that a poll carried out on, say, the Conservative party’s website, might be considerably more supportive).
Any poll actually measuring the opinion of members of the RCP would have needed to randomly sample members, or at least contact members in a way that would not have introduced any skew in those likely to reply. For all we know this may have also shown overwhelming opposition – but we cannot judge that from an open-access survey liable to have obtained an extremely biased sample.
Once again, I would urge any journalist thinking of including any polling figures in a story to look at this guidance from the British Polling Council, particularly on how to judge whether to take a poll seriously or not. If these had been looked at, the Observer should never have got to this point…
Who conducted the poll? Was it a reputatle, independent polling company? If not, then regard its findings with caution
In this case, the poll was not conducted by a polling company, but by a group lobbying against the bill they were asking about. This should have been the first alarm bell.
How many people were interviewed for the survey? The more people, the better — although a small-sample scientific survey is ALWAYS better than a large-sample self-selecting survey.
In this case, the number of people interviewed is not mentioned. It could be high, it could be low. But note Peter’s other point… this was a self-selecting survey anyway…
How were those people chosen? If the poll purports to be of the public as a whole (or a significant group of the public), has the polling company employed one of the methods outlined in points 2,3 and 4 above? If the poll was self-selecting — such as readers of a newspaper or magazine, or television viewers writing, telephoning, emailing or texting in — then it should NEVER be presented as a representative survey.
This was a self-selecting poll of doctors directed there from a site campaigning against the legislation. There is no way it should have been presented as a representative survey.
UPDATE: Credit where it is due. Denis Campbell, one of the authors of the piece, wrote about the same poll on the Guardian’s rolling blog the next day, but this time caveated it with “But that was to a website run by anti-Bill doctors and a self-selecting rather than scientific poll, so may not reflect opinion precisely.” In a perfect world I’d hope that journalists would spurn non-representative polls completely, but progress nonetheless.
Filed under:
CMRoP,
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Voodoo
