Prospective research in health service settings: health psychology, science and the 'Hawthorne' effect.

Health service providers sometimes express concern about the impact of prospective survey research upon patient behaviour. To date, there is little available evidence from which to estimate the likelihood of any 'Hawthorne' effect on patient behaviour in health service settings. We analysed data from one of our own surveys to investigate whether inviting people to participate in research had any impact on their subsequent uptake of a screening service. Findings showed that people sent a questionnaire were slightly faster to take up screening than those not sent a questionnaire. We obtained no significant difference in absolute service uptake rate at six months.