Recruiting Participants for Population Health Intervention Research: Effectiveness and Costs of Recruitment Methods for a Cohort Study

• Published in: Journal of medical Internet research 2021-11, Vol.23 (11), p.e21142-e21142
• Main Authors: Wasfi, Rania, Poirier Stephens, Zoe, Sones, Meridith, Laberee, Karen, Pugh, Caitlin, Fuller, Daniel, Winters, Meghan, Kestens, Yan
• Format: Article
• Language: English
• Subjects: Adult; Advertisements; Bias; Campaigns; Canada; Cities; Cohort analysis; Cohort Studies; Cost analysis; Female; Gift cards & certificates; Humans; Imbalance; Internet; Intervention; Linear analysis; Low income groups; Mailing lists; Mass media; Medical research; Mobility; News media; Original Paper; Participation; Performance indicators; Physical activity; Population; Population Health; Public health; Questionnaires; Recruitment; Research Design; Smartphones; Social Media; Social networks; Sociodemographics; Women
• ISSN: 1438-8871; 1439-4456; 1438-8871
• DOI: 10.2196/21142

Public health research studies often rely on population-based participation and draw on various recruitment methods to establish samples. Increasingly, researchers are turning to web-based recruitment tools. However, few studies detail traditional and web-based recruitment efforts in terms of costs and potential biases. This study aims to report on and evaluate the cost-effectiveness, time effectiveness, and sociodemographic representation of diverse recruitment methods used to enroll participants in 3 cities of the Interventions, Research, and Action in Cities Team (INTERACT) study, a cohort study conducted in Canadian cities. Over 2017 and 2018 in Vancouver, Saskatoon, and Montreal, the INTERACT study used the following recruitment methods: mailed letters, social media (including sponsored Facebook advertisements), news media, partner communications, snowball recruitment, in-person recruitment, and posters. Participation in the study involved answering web-based questionnaires (at minimum), activating a smartphone app to share sensor data, and wearing a device for mobility and physical activity monitoring. We describe sociodemographic characteristics by the recruitment method and analyze performance indicators, including cost, completion rate, and time effectiveness. Effectiveness included calculating cost per completer (ie, a participant who completed at least one questionnaire), the completion rate of a health questionnaire, and the delay between completion of eligibility and health questionnaires. Cost included producing materials (ie, printing costs), transmitting recruitment messages (ie, mailing list rental, postage, and sponsored Facebook posts charges), and staff time. In Montreal, the largest INTERACT sample, we modeled the number of daily recruits through generalized linear models accounting for the distributed lagged effects of recruitment campaigns. Overall, 1791 participants were recruited from 3 cities and completed at least one questionnaire: 318 in Vancouver, 315 in Saskatoon, and 1158 in Montreal. In all cities, most participants chose to participate fully (questionnaires, apps, and devices). The costs associated with a completed participant varied across recruitment methods and by city. Facebook advertisements generated the most recruits (n=687), at a cost of CAD $15.04 (US $11.57; including staff time) per completer. Mailed letters were the costliest, at CAD $108.30 (US $83.3) per completer but served to reach older participants. All m