CAPS on the move: Crafting an approach to recruitment for a randomized controlled trial of community gardening

To describe and evaluate recruitment approaches for a randomized controlled trial (RCT) of community gardening in Denver, Colorado. (ClinicalTrials.gov: NCT03089177).

We used community and staff feedback to adapt our recruitment approach from year 1 to year 2 of a multi-year RCT to address health behaviors related to cancer prevention. In year 2, we added a full-time recruitment coordinator, designed and implemented a tracking spreadsheet, and engaged advisory committee members, local garden leaders, and health partners in planning and outreach. Screening and consent rates, staff time and costs for years 1 and 2 are compared.

In year 1, recruitment methods yielded 136 initial contacts, 106 screenings and 64 consented participants. In year 2, enhanced staffing and outreach yielded 257 initial contacts, 193 screenings, and 123 consented participants. Personal referrals, health fairs, NextDoor, and fliers yielded the highest percentage of consented participants. School and community meetings yielded the lowest yield for potential participants. Spanish-speaking participants were mostly recruited by direct methods. Compared to year 1 recruitment, which required 707 h of staff time and cost $14,446, year 2 recruitment required 1224 h of staff time and cost $22,992. Average cost for retained participants was $226 (year 1) and $186 (year 2).

Those planning pragmatic clinical trials with recruitment in multi-ethnic communities can use the results from this study to understand the efficacy of techniques, and to budget costs for recruitment. While our culturally-tailored recruitment methods cost more, they provided more effective and efficient ways to reach recruitment goals.