Intended for healthcare professionals

Research Article

Sample size for beginners.

British Medical Journal 1993; 306 doi: (Published 01 May 1993) Cite this as: British Medical Journal 1993;306:1181
  1. C D Florey
  1. Department of Epidemiology and Public Health, University of Dundee, Ninewells Hospital and Medical School.


    The common failure to include an estimation of sample size in grant proposals imposes a major handicap on applicants, particularly for those proposing work in any aspect of research in the health services. Members of research committees need evidence that a study is of adequate size for there to be a reasonable chance of a clear answer at the end. A simple illustrated explanation of the concepts in determining sample size should encourage the faint hearted to pay more attention to this increasingly important aspect of grantsmanship.