Rapid Responses to:

LETTERS: Eric Boyd, Joao Calinas-Correia, Richard Doll, and Richard Peto Smoking and dementia in male British doctors BMJ 2000; 321: 378a [Full text]

Rapid Responses: Submit a response to this article

Rapid Responses published:

Chalmers and Altman didn't; but Eysenck did!

Iain Chalmers   (5 August 2000)

Chalmers and Altman didn't; but Eysenck did! 5 August 2000
Iain Chalmers, Director UK Cochrane Centre Send response to journal: Re: Chalmers and Altman didn't; but Eysenck did!	In his comments on the paper by Richard Doll and his colleagues, Dr Calinas-Correia suggests that Chalmers and Altman analysed the work of Janerich et al about passive smoking and lung cancer. We didn't, but Eysenck (1) did in a book that Doug Altman and I co-edited. Hans Eysenck, like Ronald Fisher before him, promoted the notion that the association between smoking tobacco and lung cancer is not causal, but reflects a predisposition to both in people with certain genetic or psychological characteristics. As Doll and Peto note in their response (2) to Calinas-Correia, however, selective citation of evidence (whether inadvertent or calculated) can be misleading. The main message of the book that Calinas-Correia cites incorrectly is that people reviewing research evidence should take steps to reduce bias, and when possible, the effects of the play of chance. I hope that the forthcoming 2nd edition (3) will succeed in communicating this message more effectively than the 1st edition appears to have done! Iain Chalmers 1. Eysenck HJ. Problems with meta-analysis. In: Chalmers I, Altman DG, eds. Systematic reviews. London: BMJ Books, 1995. 2. Doll R, Peto R. Smoking and dementia in male British doctors. BMJ 2000;321:379. 3. Egger M, Davey Smith G, Altman DG (eds). Systematic reviews in health care: meta-analysis in context. 2nd edition, BMJ Books, 2000.