Intended for healthcare professionals


Authors may have underestimated number of young doctors still working in NHS

BMJ 1999; 318 doi: (Published 29 May 1999) Cite this as: BMJ 1999;318:1486
  1. G H Hall, Former chairman, Central Manpower Committee (harry.hall{at}
  1. Ballamount, Broadclyst, Devon EX5 3BJ

    EDITOR--Lambert and Goldacre estimate that about 17% of doctors who qualified from British medical schools in 1983 and 1988 are not now working in the NHS.1 Their calculation, which was based on the capture-recapture method, depends on the assumption that the probabilities of responding to either of the two inquiries (Medical Careers Research Group and Department of Health) are statistically independent of each other.

    Suppose, however, that there is a link—that a person answering one inquiry is more likely to respond to the other, and the converse. A twofold difference in this propensity would increase the estimated number of additional doctors in the NHS from 147 to 294 and the participation rate from 83% to 87%. This is a less worrying proportion and indicates the advisability of including a sensitivity analysis by varying the basic assumptions as well as the confidence interval for the error of the method.