Questionnaires and postal research: more than just high response rates

Editor,—In the recent editorial by Bates and Rogstad1 the authors describe the problems associated with conducting postal research including response rates, use of incentives, bias, mailing clinical specimens, and ethical issues. We would like to add that there are other important issues to consider when undertaking questionnaire research. The effectiveness of incentives to increase response rates remains controversial. Kalantar and Talley2 recommend using a lottery incentive as it increases response rates after the first mailing. However, differences between groups were not large, and decreased during follow up and disappeared by the fourth mailing. Koloski et al 3 found that the use of lottery tickets increase response rates, but may be limited when using them with long questionnaires (32 pages). Moreover, they compared …