AUTHOR=Klee Bianca , Costa Daniela , Frese Thomas , Knoechelmann Anja , Meyer Gabriele , Meyer Thorsten , Purschke Oliver , Schildmann Jan , Steckelberg Anke , Mikolajczyk Rafael 

TITLE=To Remind or Not to Remind During Recruitment? An Analysis of an Online Panel in Germany

JOURNAL=International Journal of Public Health

VOLUME=69

YEAR=2024

URL=https://www.ssph-journal.org/journals/international-journal-of-public-health/articles/10.3389/ijph.2024.1606770

DOI=10.3389/ijph.2024.1606770

ISSN=1661-8564

ABSTRACT=<p><bold>Objective:</bold> To explore the role of reminders in recruiting and maintaining participation in an online panel.</p><p><bold>Methods:</bold> 50,045 individuals from five German federal states were invited by regular mail to participate in the online study “Health-Related Beliefs and Healthcare Experiences in Germany.” Those who did not respond to the first attempt received a postal reminder. Comparisons of sociodemographic characteristics and responses were made between first-attempt respondents and those who enrolled after the second letter.</p><p><bold>Results:</bold> After the initial letter, 2,216 (4.4%, 95%CI: 4.3%–4.6%) registered for the study; after a reminder 1,130 (2.5%, 2.3%–2.6% of those reminded) enrolled. Minor sociodemographic differences were observed between the groups and the content of the responses did not differ. Second-attempt respondents were less likely to participate in subsequent questionnaires: 67.3% of first-attempt vs. 43.3% of second-attempt respondents participated in their fourth survey. Recruitment costs were 79% higher for second-attempt respondents.</p><p><bold>Conclusion:</bold> While reminders increased the number of participants, lower cost-effectiveness and higher attrition of second-attempt respondents support the use of single invitation only for studies with a similar design to ours when the overall participation is low.</p>