The Use of Controls in the Assessment of Clinical Evidence

The prize-winning essay from the B.M.A. Essay Competition for Provisionally Registered General Practitioners. 1961. The essay is abridged.The incorporation of standards or controls into clinical experimentation has become, over the past decade, a widely accepted practice. So much so that there is a danger that the medical profession in general may become uncritical of the practical and, more important, the ethical problems involved. The subject should be under constant review.Are controls really necessary? How best can they be employed? How is the resulting evidence to be assessed? Under what circumstances can the use of controls be justified on ethical grounds