I agree with Yano that scientific integrity should be maintained and researchers be free from pressure from commercial and campaigning interests. I disagree that I have caused any “distortion of scientific findings” or “misrepresentation and misappropriation” of results, serious charges which I will show are unjustified. To clarify the situation I will start with the history preceding the study.

In 1981 Hirayama reported an increased lung cancer risk in non-smoking women married to smokers.¹ Following this I demonstrated random misclassification of smokers as non-smokers, coupled with smokers tending to marry smokers, leads to an observed increased risk even when environmental tobacco smoke (ETS) has no effect.^2,3 The tobacco industry then agreed to support a study in England of this “misclassification bias”, using cotinine to validate smoking, which was reported in 1987.⁴ I also reviewed evidence on misclassification,⁵ revealing the lack of useful data in Japan, where cultural differences might affect reporting of smoking.

Several tobacco companies therefore decided to fund a study there. The protocol, drafted by Proctor and discussed with me, included two major phases. …