Clinical trial feasibility often begins with a seemingly straightforward question: How many patients meet the study’s eligibility criteria?
Advances in real-world data, claims analysis, electronic health records, and artificial intelligence are helping research teams answer that question with greater speed and precision. Sponsors can estimate disease prevalence, model the effect of different eligibility criteria, identify geographic concentrations of potential participants, and locate sites that appear to serve the right patient populations.
Those capabilities are improving clinical trial planning, but they address only part of the challenge. A patient may be eligible for a study without being realistically recruitable. The difference between those two categories can determine whether enrollment projections translate into actual participation.
Eligibility Is Only the Beginning
Patient availability is generally based on characteristics that can be identified or estimated through data. A person may have the relevant diagnosis, treatment history, laboratory values, disease stage, or demographic profile required by the protocol.
Recruitability depends on a much broader set of circumstances. Can the patient be identified by a provider who knows about the study? Is there a participating site within a reasonable distance? Does the patient understand clinical research and trust the organizations involved? Can the individual manage the visit schedule, transportation requirements, procedures, time away from work, and other demands associated with participation?
Each additional condition narrows the population that can realistically enroll. A feasibility model may identify thousands of potentially eligible patients, but the operational path connecting those patients to the study may be weak, fragmented, or nonexistent.
Access Does Not Guarantee Participation
Expanding access to clinical trials remains essential, particularly for patients who receive care outside major academic medical centers. However, proximity to a study site or awareness of an opportunity does not automatically create willingness to participate.
People evaluate clinical trials through the context of their own lives. Their decisions may be shaped by concerns about receiving an investigational treatment, uncertainty about additional procedures, previous experiences with the healthcare system, family responsibilities, financial pressures, or distrust of research institutions. Some may be interested in participating but unable to accommodate frequent visits or extensive travel.
These considerations are difficult to capture through traditional feasibility data. They require patient research, behavioral insight, community engagement, and direct conversations with the people a study is intended to reach.
Providers Are a Critical Part of the Recruitment Pathway
Many patients first learn about clinical trials through physicians and other trusted healthcare professionals. That makes provider awareness and engagement an important component of recruitability.
A provider may care for eligible patients but lack the time, information, or infrastructure needed to discuss a study and facilitate a referral. Some may be unfamiliar with available trials or uncertain about what participation would mean for their ongoing relationship with the patient. Others may have concerns about sending patients to a distant research center or losing visibility into their care.
Feasibility planning should therefore examine the complete referral pathway, not simply the number of patients associated with a healthcare organization. Identifying where patients receive care, who influences their treatment decisions, and how referrals will be supported can provide a more realistic picture of enrollment potential.
Study Burden Changes the Recruitable Population
Protocol requirements also determine how many eligible patients can realistically participate. A demanding study does more than create inconvenience. It changes the effective size and composition of the recruitment pool.
Frequent visits may exclude people who live far from a site or lack reliable transportation. Long appointments can make participation difficult for those with hourly jobs, caregiving responsibilities, or limited paid leave. Complex digital requirements may create barriers for individuals with limited connectivity or comfort using technology. Invasive procedures can reduce willingness even when patients otherwise meet every eligibility requirement.
These effects may also introduce unintended bias. A study can appear broadly inclusive on paper while its operational requirements favor participants with greater flexibility, financial resources, digital access, or proximity to major research centers.
Evaluating patient burden during protocol development allows teams to identify these barriers while meaningful adjustments are still possible.
Caregivers Influence Recruitability, Too
For many patients, trial participation is not an individual decision. Caregivers may provide transportation, manage appointments, help interpret information, support adherence, and assume additional responsibilities throughout the study.
Their capacity and willingness can directly affect whether participation is practical. A visit schedule that appears manageable from the patient’s perspective may become unrealistic when caregiver work schedules, travel demands, childcare responsibilities, and financial pressures are considered.
Including caregivers in early research can reveal obstacles that patient-level data alone will miss. It can also help teams develop more realistic support services, communication plans, reimbursement approaches, and scheduling options.
Feasibility Must Account for Human Behavior
Data remains essential to clinical trial feasibility. It can challenge inaccurate assumptions, reveal geographic opportunities, estimate the impact of eligibility criteria, and help teams prioritize sites and populations. However, a model that stops at patient identification risks confusing theoretical availability with enrollment potential.
A more complete feasibility process combines population data with behavioral, operational, and human insight. It asks not only whether eligible patients exist, but whether they can be reached through trusted channels, whether the study fits within their lives, and whether they have meaningful reasons to participate.
The objective is not simply to produce a smaller or more conservative enrollment estimate. It is to understand what must be true for participation to become possible.
Clinical trials become more feasible when sponsors design around that reality. Knowing where eligible patients are is valuable. Understanding what will enable them to participate is what turns availability into recruitment.
Continue the Conversation at SCOPE Summit Europe
Patient recruitment, feasibility, and trial design continue to evolve as sponsors seek more realistic ways to identify, reach, and engage potential participants. At SCOPE Summit Europe, leaders from across the clinical research ecosystem will explore how data, technology, and patient insight can support more feasible studies and stronger enrollment strategies.
Learn more and register here.