Non-response bias versus response biasBMJ 2014; 348 doi: https://doi.org/10.1136/bmj.g2573 (Published 09 April 2014) Cite this as: BMJ 2014;348:g2573
- Philip Sedgwick, reader in medical statistics and medical education
- 1Centre for Medical and Healthcare Education, St George’s, University of London, London, UK
Researchers used a postal questionnaire survey to investigate the career progression of NHS doctors. The questionnaire included details about past and current employment, future career plans, and when career milestones were reached. Analysis was confined to respondents working in the UK NHS (including those with an honorary NHS contract). The participants were all those who graduated from UK medical schools in 1977, 1988, and 1993. The questionnaire was sent to 10 344 graduates, of whom 7012 replied, giving a response rate of 68%.1
Men and women were compared, with the aim of establishing whether female doctors were disadvantaged in pursuing careers in the NHS. The researchers reported that women did not progress as far or as fast as men. However, it was suggested this was not because women encountered direct discrimination but that it was a reflection of not having always worked full time. Nonetheless, the possibility that indirect discrimination—for example, that the lack of opportunities for part time work may have influenced choice of specialty—could not be ruled out.
Which of the following statements, if any, are true?