By Dr. Fernando Castro, Founder & CEO, Culture Wise Insights
(Photo, courtesy of Culture Wise)
In market research, we frequently describe certain populations as "hard to reach." Hispanic consumers, patients living with chronic conditions, rural residents, and specialized professionals often receive this designation. Yet after years of recruiting qualitative research participants, I have begun questioning whether we are always identifying the real problem.
Are these individuals genuinely difficult to reach, or are our recruitment methods making them difficult to engage? The distinction matters. Being hard to reach means a population is difficult to identify or contact. Being hard to engage means eligible individuals may be accessible but reluctant or unable to participate because of barriers involving trust, communication, or technology. Understanding this difference can fundamentally change our recruitment strategies.
When trust becomes the recruitment strategy
A project involving Hispanic patients living with chronic kidney disease (CKD) reinforced this perspective. Our client required 12 individual interviews with Hispanic CKD patients, including participants with low levels of acculturation. Recruitment proved challenging, particularly among older Spanish-speaking individuals who were difficult to reach through conventional digital channels. Some potential participants were also skeptical of research invitations. Previous experiences with scams had created distrust, making unsolicited messages particularly ineffective.
Our breakthrough came when we connected with an eligible patient and personally explained the study's purpose. Rather than immediately focusing on screening questions, we discussed how patients' experiences could inform medical professional training and potentially improve care. Once the patient understood the objectives and expressed interest, we invited them to share the opportunity with others who might qualify. This opened the door to patient-to-patient referrals, connecting us with individuals who might otherwise have hesitated to engage with an unfamiliar recruiter.
We also leveraged our network of cultural brokers, including certified nursing assistant (CNA) instructors who helped us reach families of potential participants through established community relationships. By combining peer referrals with trusted community connections, we successfully recruited all 12 patients. The difference was not simply access to a larger database. It was the credibility of people whom potential participants already knew and trusted.
Of course, snowball recruitment introduces methodological considerations. Referrals can overrepresent interconnected social networks, potentially limiting sample diversity. Therefore, referred individuals should undergo independent eligibility screening, and recruitment quotas must remain consistent regardless of referral source. The lesson was clear: Sometimes effective recruitment is less about finding more people and more about building trust through the right relationships.
The human connection cannot always be automated
Technology has made recruitment faster and more scalable. However, efficiency should not be confused with effectiveness. In our experience recruiting specialized Hispanic healthcare audiences, personal telephone conversations have sometimes accomplished what repeated emails and social media messages could not.
A phone call allows potential participants to ask questions, express concerns, and understand why their experiences matter. It also enables recruiters to recognize hesitation rather than interpreting silence as disinterest. For individuals concerned about legitimacy or confidentiality, human interaction can make participation feel safer and more meaningful. Sometimes, the most effective recruitment tool is simply a genuine conversation.
When research requirements create exclusion
Another recurring challenge involves technology requirements. In advertising and concept testing, clients sometimes require laptops or desktop computers, excluding tablets and smartphones. The rationale is understandable. Certain visual stimuli require larger screens to ensure consistent presentation and reliable evaluation. However, researchers should distinguish between requirements that are methodologically necessary and those established primarily for convenience.
We have encountered otherwise qualified Hispanic participants, particularly older or less-acculturated individuals, whose smartphones were their only means of accessing the internet. This raises an important question: Are we excluding participants because they do not meet the research criteria, or because they cannot meet our technological requirements? If device restrictions disproportionately exclude certain segments, the resulting sample may not adequately reflect the intended population.
This does not mean smartphones should be permitted in every study. Some research objectives genuinely require larger screens. Rather, researchers should evaluate whether restrictions are essential, identify which populations may be excluded, and consider alternatives.
Could stimuli be optimized for mobile viewing? Could devices be provided? Could another interview format achieve the same objectives? A methodology designed to understand consumers should not unnecessarily exclude them because of how they access technology.
Rethinking what makes participation possible
Recruiting difficult populations requires more than larger incentives, broader databases, or additional screening efforts. For some audiences, the challenge is identification. For others, it is trust, accessibility, language, or technology. These challenges require different solutions.
Researchers should examine whether their recruitment strategies reflect the realities of the populations they seek to understand. The responsibility for successful recruitment cannot rest entirely on participants adapting to our research processes. Sometimes, the research process must adapt to them.
Perhaps the next time we describe a population as hard to reach, we should first ask whether we have made participation accessible enough for them to say yes.
ABOUT THE AUTHOR
Fernando Castro, Ph.D., is the founder and principal of Culture Wise Insights, a multicultural market research firm specializing in qualitative recruitment, hard-to-reach audiences, and multilingual research. With more than seven years of moderation experience, he conducts research in English, Spanish, and Portuguese, with particular expertise in Hispanic and multicultural consumers, healthcare, and B2B audiences. His work focuses on building trust with participants, strengthening recruitment quality, and helping organizations uncover culturally grounded insights that inform better business decisions. He also teaches at the university level, bringing together his backgrounds in research, education, language, and culture.