STRATEGIES TO ENHANCE RECRUITMENT AND RETENTION
Although the barriers described previously can seem daunting, there are strategies that can be used to enhance the efficiency and effectiveness of the recruitment process and participant retention. Of course, every study is different, so these strategies need to be adapted to the characteristics of the target population, context, and the intervention.
First and foremost, it is essential to have a recruitment plan and this plan must be developed early on in the pipeline. A key part of this plan must be obtaining information on the recruitment “environment” in order to obtain accurate estimates of the number of potential individuals who meet study entry criteria. If it appears that the numbers are low relative to recruitment goals, it might be necessary to expand the catchment area, and/or reexamine inclusion and exclusion criteria. It is also important to analyze the requirements and demands of participation to identify potential barriers to study enrollment and retention such as excessive time demands or transportation costs. In addition, it is important to understand the characteristics of the target population within the recruitment catchment area. The plan should also include sources for recruitment, a recruitment timeline, and contingencies in case there are recruitment lags (e.g., additional recruitment sources that might be tapped). There should also be a plan for maintaining enrolled participants (e.g., birthday greetings, check-in calls).
Sufficient resources must be allocated to both recruitment and retention. All too often investigators underestimate the cost and personnel effort associated with enrolling and maintaining participants in a study. Systems and personnel must be in place to identify and engage potential participants and to determine eligibility. Sufficient staff must be allocated to recruitment, and monies must be set aside in study budgets for recruitment efforts (e.g., costs for advertisements or travel costs of staff to attend community meetings). Staff must also be educated about the importance of participant recruitment, the recruitment timeline, and participant retention. They should also have training in working with the target population. For example, in the PRISM trial, the staff received basic training on aging and effective strategies for interacting with older adults. Culturally congruent research staff, who share similar personal characteristics (e.g., age, race/ethnicity, diagnosis) as the individuals being recruited, has been identified as an important facilitator to participant enrollment (George et al., 2014). This seems to increase trust in the research process and also allows participants to relate to and communicate with research staff in their own language and rhythm of expression (Calderon et al., 2006). Sometimes, it is helpful to have a community representative, such as an outreach worker from the target population, serve as a recruitment agent. For example, in African American communities, having a deacon or church member work with the ministers of churches may prove helpful.
Another critical aspect of recruitment is the need to establish collaborations with key members of the community and recruitment sites. These collaborations can take time and effort to foster and should be in place early in the pipeline as one is developing an intervention. Community leaders and agency representatives need to be clear about the goals and scope of the research, participant inclusion and exclusion criteria, the requirements of participation, and potential costs/benefits to the participants. It is also important to maintain frequent contact with these individuals, to not make excessive time or effort demands on them, and to maintain contact with them throughout the study.
A plan should also be in place for monitoring recruitment and retention. This is important not only for the effective implementation of the study, but also for the subsequent publication of the study results. A database for monitoring recruitment and retention should be established for the study that should include information regarding recruitment status relative to the study timeline, source of recruitment (e.g., “How did you hear about the study?”), reasons for refusal or ineligibility, actual enrollment, as well as data related to attrition (e.g., date of dropout, reasons for leaving the study). This type of data provides valuable information about adherence to the study recruitment timeline and overall effectiveness of recruitment strategies. The Consolidated Standards of Reporting Trials (CONSORT) requirements (see Chapter 24) for RCTs provide clear guidance on these issues. Data of this type can help identify fruitful sources of recruitment, problems with current strategies, and the study requirements; and it can allow corrective action to be taken early on. For example, in the PRISM trial, it was discovered that one of the factors influencing enrollment was randomization—potential participants wanted to receive computer training. Thus, the design was modified such that for those randomized to the control group (noncomputer group), the opportunity to receive computer training upon completion of the trial was provided. Although this reflected an increased cost to the trial, it effectively addressed the enrollment issue. Figure 10.1 presents an example of a graphic display depicting the number of persons inquiring about a study, the target enrollment number, and the actual enrollment number. This type of graphic provides a quick visual of month-by-month recruitment progress to help guide recruitment planning.
The nature and method of communicating with potential participants and community representatives are also critical to recruitment and retention outcomes.
Figure 10.1 Example of a study enrollment graph (cumulative to date).
Understanding the benefits of participating in the study may positively influence participant enrollment as may compensation for participation. Highlighting “the good” that can come out of their participation—not only for themselves but to their community—can be a powerful facilitator. When participants view their participation in research as altruistic—helping family members and the community in the present and future, advancing medical knowledge—then they may be much more likely to volunteer for a study (George et al., 2014). Participants must also clearly understand the goals and objectives of the study, requirements of their participation, and risks/benefits. Issues related to safety and privacy must also be addressed. For example, if individuals perceive that participation will help them achieve personal goals (e.g., weight loss studies, access to health care), they may be more likely to participate in a study (Brooks et al., 2007; Calderon et al., 2006; Farmer, Jackson, Camacho, & Hall, 2007; Zuniga et al., 2007). Communication can take many forms such as flyers, advertisement in newspapers/radio, outreach talks, announcements in libraries and other public spaces, mailings, and so forth. Irrespective of the format of the communication, it must be done in a way that is understandable by participants and that is also approved by an institutional review board.
Depending upon the monetary resources available for a study, compensation might include monetary incentives for participation, free lunch, or free health screens (Chao et al., 2011; DeFreitas, 2010). The compensation must be meaningful to individuals relative to their time and effort commitments; however, it cannot be too great as to be or appear to be coercive. Attention also needs to be paid to participants’ perceptions concerning the risk of exploitation (Brugge, Kole, Lu, & Must, 2005). If participants feel that the risk of exploitation is minimal or nonexistent, they will be much more motivated to enroll in a study.
Addressing the potential logistical barriers of a study may also help enrollment. Every effort should be made to make participation as convenient as possible. This may include soliciting employer support to allow participants to take time off to attend appointments (Wyatt et al., 2003), helping with child or eldercare (Calderon et al., 2006), arranging for transportation (Crawford Shearer et al., 2010), or compensating for transportation costs. Other strategies such as having flexible hours for participants and scheduling assessment or intervention sessions on weekends or in the evening or at a convenient place may also facilitate recruitment. Involving community consultants to understand the needs and values of the targeted population and guide recruitment and retention decisions can be instrumental in deriving an effective plan of action.
Another major concern of researchers conducting behavioral intervention trials is to decrease attrition and achieve the required follow-up contacts to meet study goals. This is a particular challenge for longitudinal studies or those involving older participants or those who are ill or frail. Participant attrition is also influenced by study characteristics such as the number and timing of follow-up contacts, the complexity of the treatment protocol, incentives for continued participation logistical issues, and skills of the research staff. Thus, some of the same strategies to enhance recruitment, such as minimizing the logistical inconveniences of study participation, establishing mutual investment in the research process, tailoring the intervention materials, and providing some form of compensation, are helpful with respect to minimizing participant attrition. It is also critical to train staff so that they have a comfortable and respectful relationship with the participants, conduct follow-up assessments in a timely manner, and understand the importance of retention. In addition, where appropriate, it is important to maintain contact with participants, especially those in control conditions, with check-in calls, messages, and thank-you notes for participation.