Does requesting sensitive information on postal questionnaires have an impact on response rates? A randomised controlled trial in the south west of England

摘要

The context of the trial reported here was a two phase community based observational study to ascertain the prevalence of various chronic conditions. The first phase entailed a postal screening questionnaire; the second involved clinical examinations of screen positives and a sample of screen negatives. To maximise com- pliance with the second phase, it was consid- ered valuable to obtain subjects' telephone numbers form the initial questionnaire. How- ever, there was concern that requesting this information might reduce the questionnaire response rate.