Improving participation rates by providing choice on participation mode: two randomized controlled trials

Abstract

This study is part of the ‘Tailored Implementation for Chronic Diseases’ (TICD) project and is integrated in a program evaluation which has been designed as a two arm randomized controlled trial (NTR4069).

Low participation rates represent a common problem in survey research. It is well known that low participation rates reduce effective sample size, statistical power and may cause selection bias. Several efforts for improving participation rates have been described in the literature. However, less research has focused on providing participants with choice on participation mode. Most research on choice for participation mode used internet-based modes as options, while such options may not be feasible for all participants groups. In this research, we investigated the effects of providing choice on participation mode for participation in a social network study among elderly patients with a chronic cardiac condition, using telephonic interviews and postal questionnaires. Two randomized controlled trials were performed using this dataset. In Trial 1 we compared invitations with choice with participation rates of invitations for a telephonic interview. In Trial 2 the choice format invitation was compared with an invitation for a postal questionnaire.