Summary: In the 12 months from July 1977 to June 1978, out of 168 papers in the British Journal of Psychiatry, 139 (83 per cent) presented numerical results. A total of 63 papers contained statistical errors and at least one drew unsupportable conclusions. In many cases the errors were not considered to be severe, but they were often sufficient to raise doubts about some inferences. It is suggested that more consultation of investigators with medical statisticians, a basic training in statistical methods in the preclinical years, and more extensive statistical refereeing are needed.