Effects of estimated completion time and unconditional gift certificates on questionnaire response

Obtaining a high response rate is important to reduce selection bias. Some strategies, including prenotification, monetary incentives and shorter questionnaires, may increase response rates, whereas other strategies have no or unclear effects.1 We determined whether the estimated completion time and/or an unconditional gift certificate affect questionnaire response. Pregnant women participating in the PRIDE Study were asked to fill out a postal food frequency questionnaire (FFQ) after completing the web-based baseline questionnaire.2 We employed three strategies to increase response rates in succession: (1) underestimation of completion time (10–15 min) without offering incentives, (2) underestimation of completion time with an unconditional 5 gift certificate for an online store and (3) correctly estimated completion time (20–30 min) with the gift certificate. When the FFQ was not returned within 4 weeks, a reminder letter was sent. We compared the total completion rate and the proportion of FFQs completed without a reminder among...
Source: Journal of Epidemiology and Community Health - Category: Epidemiology Authors: Tags: Letters to the editor Source Type: research