High quality placebos should be used

EDITOR,—In his editorial Kenneth J Rothman states that “as medical knowledge accumulates, the number of placebo trials should fall” and that “placebo control should no longer be part of the gold standard.”1 I disagree with the latter statement. The main purposes of the placebo are to protect evaluations of outcome from (i) the effects of experimenter bias, by enabling blind assessment; and (ii) the influence of patients' expectations, by controlling for non-specific aspects of health …