Walker M. A comparative study of non-responders and responders in health research.
Thesis: MA. 1986 University of Leeds.
Abstract: Non-responders may differ from responders in demographic characteristics and risk
factors; in attitudes to health and disease; in life expectancy and in the prevalence and incidence of
disease. A literature review on non-responders provided good evidence that there were many traits,
which were common across studies in non-responder profiles. They tend to be older, less well
educated and in a lower socio-economic category compared to their corresponding responders. The
non-responder is more likely to be single, does not appear to be suffering from as many symptoms
or diagnoses of disease as the responder, but has a shorter life expectancy. More non-responders
smoke and drink, and worry less about their health. Specific information from the British Regional
Heart Study was drawn from all the available death certificates of both participants and nonparticipants in the study after an average period of 6.2 years. The data revealed a small excess
annual death rate in non-responders, which persisted throughout the first five years of follow-up.
Cause of death was not significantly different between the two groups, nor was the place of death
(home vs. hospital) or geographic mobility. A highly significant difference was found in "informant"
of the death, suggesting a lower proportion of non-participants with a close/dependent family. Both
manual working status and non-participation contribute independently to the excess death rate
found in non-participants and these results were not confounded by age. Clearly, if response rates
are low the data derived from the participating sample will introduce a measure of inaccuracy and
bias into most prevalence and incidence studies. Every epidemiological study should be concerned
to obtain as much information as possible on the non-responders in order to assess the bias
introduced into the data and improve its interpretation.