COMARE's mistaken attack on the Parents Concerned About Hinkley (PCAH) questionnaire survey of cancer in Burnham-on-Sea, Somerset, UK.
Their first mistake - not a 30% response to a 100% sample, but
a 100% response to a 30% sample -
and the illogical mess they've made after admitting it

COMARE have admitted their mistake about the size of the sample and the scale of the response and have amended their Statement. This page addresses the fact that while before the revision their Statement was merely wrong it now contains logical inconsistencies as well, bringing their competence severely into question.
Secondly, after nearly a year COMARE has ignored all the other points in our response. They remain to be answered. We conclude that their Statement was and is a political exercise, intended to damp down concern among local councillors and local news media.
We note that Dr Julia Verne, Director of the South West Cancer Intelligence Service, on whose report COMARE relied heavily in preparing their own Statement, is now a member of COMARE.
How cosy. Click here to see the main problem with Dr Verne's report - i.e. that it denies a sea-coast effect which is apparent in its data.

Here we reproduce parts of section 4 of the COMARE Statement
COMARE's text is in black.
We have copied back in the text they deleted from the original in orange
Text inserted by COMARE in the amended version is in green.
Our comments are in red.

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COMARE Statement Section 4. The two studies

A house-to-house survey that relies on volunteers is bound to be flawed in several ways. The 30%
(inserted) sampled may not
(deleted) of participants who responded are unlikely to
be representative of the whole population. LLRC comments: The sample was 30% of the whole ward and response was virtually 100%. The sample was 1500 randomly selected people, consisting of those who lived (or who had lived) in those houses where someone was at home when the volunteers called. The calls were made at weekends. Little if any bias would have been introduced by this method, so it is a representative sample and it is big enough to confer statistical significance on the results.

...

Various independent studies suggest that the ascertainment of cases by cancer registries is generally quite high (up to 95% for some adult cancers and higher for childhood cancers) and thus represents a very different dataset to that gathered by Green Audit (Huggett, 1995). It was possible for the cancer registry to count the number of cancers in the whole population of Burnham North in the time span of the Green Audit study. It is not known if the cancer registry case count includes the cases found by Green Audit but the total case numbers of cancers known to the cancer registry is considerably greater than the 64 cases reported by Green Audit. For all cancers those 64 cases represent only 27% of cases known to the registry. Likewise the figures for breast (38%), prostate (39%) and lung (15%) all show that the Green Audit seriously under-ascertained cancer cases in Burnham. LLRC comment: This is absolute nonsense. Since the survey covered 30% of the population (which COMARE now acknowledge) finding almost 30% of the cases is a good result. Curiously the Green Audit counts for cervix and kidney were almost the same as the cancer registry figures, indicating that Green Audit's figures are almost certainly erroneously too high, given that they are looking at only 30% of the population. This is not surprising given the methods used. Equally, therefore, it is not surprising the results of the two studies are different. LLRC comment: Since this inverts the logic they used in the first part of this paragraph it seems that they didn’t think this through either in their original statement or in the revision. We have already said (in our original response) that it is indeed curious that the PCAH volunteers apparently found all the kidney and cervical cancer cases, but the point that really needs explaining is that Burnham has large, undisputed and statistically significant excesses of both these cancers. Would we ever have known about this if PCAH hadn’t had the guts to go out and get the data direct from the public?

The Green Audit study is biased in several ways LLRC comment: they identify only two principal problems and the results show the flaws inherent in the approach they adopted. In commenting on this work we do not wish to criticise either the idea of carrying out such a survey or the involvement of the local community.LLRC comment: this is a welcome, if small, concession. There are, however, well-recognised methodological problems in such work, and the failure by Green Audit to take account of these will have led to unreliable conclusions. Two (not several) principal problems are, first, the likelihood of bias in the results because of the very low response rate (They have already conceded that this assumption was a mistake) and, second, the possibility that the self-reported information on medical diagnoses is incompatible with that in medical records. In order to avoid these possible biases, it is essential first to obtain a high response rate either from the whole of the population being surveyed or from a sample that adequately represents it. If this is not done, it has to be assumed that those who do respond are very likely to be in some way different from the general population. This could result in reported cancer rates being either too high or too low, and the reported data on cancer rates should be validated by a check on the survey responses against medical records.
LLRC comment: As noted above, PCAH did obtain a high response rate (actually the highest conceivable) from a large and adequately representative sample. Why has COMARE failed to amend its position on possible bias after accepting that they were wrong about the sample? We conclude that it's because they are over-influenced by the views of the International Commission on Radiological Protection, according to which the radiation doses from the contaminated mud flats near Burnham are too small to have any visible effect on human health. COMARE lacks the scientific rigour and the courage needed to think its way out of this box and, as a result, violently attacks anything which challenges their (ICRP's) view.
We agree that the reported data should be checked against medical records, but this is not remotely possible for a doorstep survey by local volunteers. COMARE does not seem to live in the real world - the point of the survey was to indicate whether or not there was a health problem and, if a positive result were demonstrated, to persuade the authorities to act.

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What you can do about this:

• Write to your MP asking him or her to sign Early Day Motion 1548, which proposes to scrap COMARE.
• Print out the previous page and send it to COMARE asking for a full reponse. The address is Dr. Roy Hamlet, COMARE Secretariat, National Radiological Protection Board, Harwell, Didcot, Oxfordshire OX11 0RQ
• Alternatively, send it to Dr John Reid, Secretary of State for Health, Department of Health, Richmond House, 79 Whitehall, London SW1A 2NS

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References

COMARE 2003 Statement on Green Audit Occasional Paper 2002/5 “Cancer in Burnham on Sea North: Results of the Parents Concerned About Hinkley (PCAH) Questionnaire” (COMARE 25th November 2003)[http://www.comare.org.uk/statements/comare_statement_burnham.htm] (This hot link takes you to their amended version. The original is no longer on the COMARE web site. We can email it to you if you want it.)

(For other references see previous page)