Authors' replyBMJ 1995; 310 doi: https://doi.org/10.1136/bmj.310.6990.1328b (Published 20 May 1995) Cite this as: BMJ 1995;310:1328
- C B Del Mar,
- A C Green
- Reader in general practice University of Queensland Medical School, Brisbane, Queensland 4006, Australia
- Principal research fellow Queensland Institute of Medical Research, Brisbane, Queensland 4029, Australia
EDITOR,—David de Berker is right to point to some of the weaknesses in our study, which we discussed. We wish that we could have randomised several cities to each arm of the study to increase the likelihood that any effect we found was attributable to the intervention and not to alternative factors in one city.
It is incorrect to ascribe the relative change in potentially malignant lesions to only the absolute increase in potentially malignant lesions (from 78 to 112 a …