Effective and resource efficient strategies for recruiting families in physical activity, sedentary behaviour, nutrition, and obesity prevention research: A systematic review with expert opinion

Abstract

Background: The recruitment of participants into intervention research has been notoriously difficult for research teams around the world, where many researchers fail to recruit 100% of their target sample size within their pre-agreed timescale. The recruitment of families into experimental research projects is also challenging, yet there has not been a comprehensive assessment of how to recruit families to family-based health promotion research. Therefore, we systematically identified effective and resource-efficient strategies for recruiting families into health promoting intervention research. Methods: Four databases were searched for published reviews. Intervention studies were extracted from included reviews. Subsequently, a Delphi study was conducted with 35 experts in relevant family-based research. We assessed extracted data from our review and Delphi participants’ opinions by collating responses into overarching themes based on recruitment setting and recruitment strategies to identify effective and resource-efficient strategies for recruiting families into intervention research. Results: A total of 64 articles (n = 49 studies) were included. Data regarding recruitment duration (33%), target sample size (32%), reach (18%), expressions of interest (33%), and enrolment rate (22%) were scarcely reported. Recruitment settings (84%) and strategies (73%) used were available for most studies. However, the details were vague, particularly regarding who was responsible for recruitment or how recruitment strategies were implemented. The Delphi showed recruitment settings and strategies fell under 6 themes: school-based, print/electronic media, community settings-based, primary care-based, employer-based, and referral-based strategies. The most common recruitment setting was in schools and the most common recruitment strategies were passive strategies (e.g., sending letters). Of the Delphi participants, 62% reported under-recruitment in their most recent family-based experimental study. Discussion: Under-recruitment in family-based trials is a major issue. Moreover, most studies applied similar recruitment strategies, predominantly through schools, despite known challenges of recruiting in schools. Our findings suggest that researchers should employ a multifaceted recruitment approach that targets adults and children and provides potential participants with repeated exposure to study information. Reporting on recruitment can also be improved by better adherence to existing guidelines. Improved reporting around effectiveness of recruitment will give future researchers the ability to better budget their time, resources, and provide greater confidence in meeting their target sample size. Future research should investigate the estimated cost of recruiting families into trials; as well as more sophisticated and innovative research strategies (e.g., consulting experts in data science, marketing, advertising, graphic design, social media). Conflict of interest: We have no conflicts of interest to declare.