Recruitment plans start with a headcount: this many patients with the condition, in these regions, so the trial is feasible. The math looks sound. The patients are real. Then enrollment stalls, and the assumption underneath the plan goes unquestioned: that a patient who exists is a patient the trial can reach. Those are two different things. And the gap between them is where feasible-on-paper studies quietly fall behind The access gap is measurable. In one 2024 lung cancer Medicaid analysis , only 57% of metastatic patients had evidence of any biomarker testing, a prerequisite many modern protocols depend on. A patient is available if they have the condition. They are accessible only if they can travel the distance from interested to enrolled.