Editor - Taylor et al came to the conclusion that "this study has
failed to confirm our original hypothesis that homeopathy is a placebo"
. Unfortunately, the statistics do not prove that.
The basis for the study was a prestudy power calculation  which
required 120 patients to prove the hypothesis, with a 5% significance and
an 80% power, infact only the study only recruited 51 patients, but
analysed the results as if they had the required number. In fact their
only conclusion was that they do not have enough data to make a
If we accept the availability of only 51 patients at the outset, what are
the relevant calculations ? The power calculation is only 43%, and to
maintain the power calculation at 80%, the "p-value" becomes 34% !
The only conclusion is that the trial is not able to prove anything.
Royal Oldham Hospital,
Oldham OL1 2JH.
1. Taylor MA, Reilly D, Llewellyn-Jones RH, McSharry C, Aitchison TC.
Randomised controlled trial of homoeopathy versus placebo in perennial
allergic rhinitis with overview of four trial series. BMJ 2000; 321: 471 -
476. (19-26 August).
2. Reilly DT, Taylor MA, McSharry C, Aitchison T. Is homoeopathy a
placebo response? Controlled trial of homoeopathic potency, with pollen in
hayfever as model. Lancet 1986; ii: 881-886
Competing interests: No competing interests