There are numerous participant-related factors that may prevent a person from enrolling in a research project. Having an awareness of these issues can help with the development of strategies to minimize them. In general, demographic characteristics such as a person’s age, health status, socioeconomic status (SES), and cultural/ ethnic identity influence recruitment. Higher rates of refusal are often found among persons with less education or less income or lower health knowledge (Gul & Parveen, 2010). It is also typically more difficult to recruit minorities and older adults or dyads (e.g., patient and caregiver).
A historic problem and well-documented barrier to recruitment that continues to pose a formidable barrier to research participation, especially among minority populations, is mistrust of research and the research process (Crawford Shearer, Fleury, & Belyea, 2010; George et al., 2014). The Tuskegee Study is just one example of the history of systematic abuse and mistreatment in both health care and medical research for African Americans (Scharff et al., 2010). As a consequence of that incident, for many African Americans, their mistrust in research participation is associated with the perception that research will benefit Whites or the research institution and not people of color (Katz et al., 2008; Scharff et al., 2010). Similarly, Native Hawaiians have reported mistrust related to the fear of purposeful mistreatment and that the researcher’s agenda is not to serve their community (Gollin, Harrigan, Calderon, Perez, & Easa, 2005). Among Latinos, there is the fear that participating in research may lead to deportation (Calderon et al., 2006). Such mistrust in itself is likely to lead to stigmatizing attitudes toward participation in clinical research (Jang, Chiriboga, Herrera, Tyson, & Schonfeld, 2011; Link & Phelan, 2014). In fact, recruitment of minority populations continues to be a challenge for many intervention trials and has become a priority of funding agencies such as the National Institutes of Health. The need for increased ethnic minority recruitment reflects the changing demographic composition of the United States, which is increasingly multiethnic and pluralistic. Increased proportions of minorities in intervention studies will also allow for subgroup analyses to examine if race/ethnicity moderates the outcomes and will enhance the generalizability of the findings to diverse groups (Yancey et al., 2006).
In the context of behavioral intervention research, stigma may be related to the study topic of interest (Conner et al., 2010; Jimenez, Bartels, Cardenas, & Alegria, 2013; Zuniga, Blanco, Martinez, Strathdee, & Gifford, 2007). This in turn may negatively impact recruitment. For example, participants may be reluctant to participate in research for fear of the social repercussions of disclosing sexual preference, HIV status, or substance abuse (Brooks, Newman, Duan, & Ortiz, 2007). For those struggling with mental illness, the lack of acceptance and support from family members may manifest itself in deciding whether to participate or not in a study (Jimenez et al., 2013).
Recruitment of older adults may also pose challenges. This group may be fearful about the research process or simply lack the stamina to participate if a study is effortful in terms of time or energy demands. Their family members may also advise them against participating because of concerns that they are being exploited. Special challenges arise when recruiting individuals with cognitive impairments or life-threatening illnesses. Often, recruitment in these cases involves a surrogate or caregiver, and there are ethical issues to consider concerning the consent process and data collection protocols (see Chapter 13).
Lack of effective strategies for communicating effectively to potential participants, such as tailoring recruitment materials to the characteristics of the target population, also represents a barrier to recruitment. For example, among non- or limited- English-speaking racial/ethnic minority participants, the lack of bilingual research staff and informational material in languages other than English is a barrier (Calderon et al., 2006; Giarelli et al., 2011). Similarly, advertisements in magazines, newsletters, newspapers, and on radio have proven to be ineffective ways of communicating with participants who are very familiar with digital media and technologies (Griffin, O’Connor, Rooney, & Steinbeck, 2013). The literature also suggests that effective means of advertising vary as a function of ethnicity/culture. For example, in the Personal Reminder Information and Social Management System (PRISM) for Seniors trial, it was found that the Hispanic participants responded more favorably to community outreach activities, whereas the primary sources of recruitment for African American participants were more varied and included community outreach, flyers/ brochures, and word of mouth (Czaja et al., 2015).
Other participant-related factors that may influence enrollment decisions include safety concerns related to perceived risks associated with the intervention and privacy concerns related to the use or potential exposure of personal data.
Contextual and sociocultural variables also influence enrollment of participants. The characteristics of the research site may deter potential participants from enrolling in a trial. For example, the perceived safety of the neighborhood, parking facilities, travel distance, and other factors such as cleanliness and access to snacks are important variables. Sociocultural factors such as values and belief systems of the participants or the perceptions of the research institute by the community also need to be considered.