COMMON ISSUES WITH RECRUITING STUDY PARTICIPANTS
As noted, recruitment of study participants is often a challenge for investigators at all stages of the pipeline, but this is especially the case in the efficacy and effectiveness phases when an intervention is being evaluated. Common problems include difficulty identifying targeted participants, the need to change participant inclusion/ exclusion criteria, slow rates of recruitment, and failure to meet recruitment goals. For example, a review of 114 multicenter randomized controlled trials (RCTs) conducted in the United Kingdom between 1994 and 2002 (McDonald et al., 2006) indicated that less than 31% of the trials achieved their original recruitment goals; about half (53%) needed to extend their recruitment timeline; and the majority (63%) reported problems early in the trial with recruitment.
There are numerous challenges to recruitment, especially for certain study populations such as older adults, minorities, or those with a chronic or debilitating illness. Recognizing that each intervention study, target population, and context is unique, in this section we discuss common issues and challenges in recruitment and factors that deter or enhance participation in behavioral intervention research. Having an understanding of these issues early on in the intervention pipeline will facilitate enrollment of study participants and ultimately enhance the efficiency and cost-effectiveness of a study and the strength of the evidence regarding the impact of the intervention. Recruitment strategies can be developed on a broad platform and then adapted to meet the particular specificities of targeted groups and contexts. When recruitment materials and methods resonate within the target community, members of that community are more likely to participate in the research trial (George et al., 2014).