Abstract
Losses in follow-up that are biased with respect to outcome invalidate the results. There are many ways of dealing with non-response in follow-up studies. Three separate methods were used to investigate a potential bias in a mail survey of 2471 disabled people. At a response rate of 84%, the non-respondents were significantly different from the respondents with respect to the outcome, return to work and vocational training. The success rate in terms of the outcome was negatively related to the number of reminders. Significant differences were found in response rates according to age, social class, impairments, previous employment record, and completion of rehabilitation courses. There is no safe level of response rates below 100%. However small the non-response, a possible bias as a result of it must be investigated.
Full text
PDF



Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cartwright A. Professionals as responders: variations in and effects of response rates to questionnaires, 1961-77. Br Med J. 1978 Nov 18;2(6149):1419–1421. doi: 10.1136/bmj.2.6149.1419. [DOI] [PMC free article] [PubMed] [Google Scholar]
- LAURENCE K. M. Tracing patients. Lancet. 1959 Aug 29;2(7096):208–212. doi: 10.1016/s0140-6736(59)90159-x. [DOI] [PubMed] [Google Scholar]
- Rose G., Barker D. J. Conduct of surveys. Br Med J. 1978 Oct 28;2(6146):1201–1202. doi: 10.1136/bmj.2.6146.1201. [DOI] [PMC free article] [PubMed] [Google Scholar]