When a CRO sends a feasibility questionnaire to a potential clinical trial site, they are asking one question in many different ways: can this site enroll the patients it says it can, as fast as it says it can? The specific items on the questionnaire — patient population numbers, coordinator capacity, previous trial experience, regulatory infrastructure — are all proxies for the answer to that question.
Sites that answer feasibility questionnaires with data rather than estimates win more studies. Sites that answer with estimates — or worse, with optimistic projections the PI generates from memory — get selected less frequently and are removed from studies more often. Understanding exactly what CROs are evaluating, and why a physician referral network directly addresses their primary concern, changes how a site competes for study grants.
The Four Things CROs Are Actually Measuring
Published research on sponsor and CRO site selection criteria consistently identifies four primary factors. First-patient-in speed — how quickly a site can enroll its first patient after activation — is rated the most important factor by 42 percent of CRO decision-makers. Historical enrollment rate — what percentage of its enrollment target the site achieved in past studies — is identified as the single strongest predictor of future performance. Screen failure rate and database query rate round out the top four, both serving as data quality proxies.
Cost is consistently ranked as less important than speed. A 2019 study published in PMC found that 88 percent of sponsors and CROs would prefer reaching enrollment goals 10 percent faster over cutting costs by 20 percent. Sites that focus primarily on budget negotiation in feasibility discussions are optimizing for the wrong variable.
What a Physician Referral Network Provides on a Feasibility Questionnaire
When a CRO asks "how many patients do you expect to enroll per month?" a site with a physician referral infrastructure answers differently than one without it. Instead of the PI estimating from their own patient panel, the site produces a number derived from the actual count of eligible patients in the geographic area — derived from NPI data and regional prevalence statistics — and the documented number of physicians currently receiving referral outreach from the site.
That answer is more credible. It is based on methodology the CRO can understand and audit. It demonstrates that the site has an enrollment system rather than an enrollment plan. And it directly addresses the CRO's primary concern: can this site produce patients at the rate it is projecting.
The Feasibility Questionnaire as a Competition
Sites rarely think of feasibility responses as competitive documents, but they are. The CRO is evaluating multiple sites simultaneously, often in the same geography. A site that responds quickly, with data-supported enrollment projections and documented outreach infrastructure, appears more capable than a site that takes two weeks to respond with estimates based on PI recall.
Sites that have completed NPI-based physician identification for the relevant therapeutic area can respond to feasibility questionnaires with a physician contact count, an active outreach count, and a documented enrollment-per-physician-contacted conversion rate from previous studies. Sites without that infrastructure respond with a number the PI came up with because it seemed reasonable. The CRO selection outcome reflects the difference.
How Historical Performance Compounds
CROs maintain internal databases of site performance across studies. Sites that consistently enroll 80 percent or more of their target within timeline build a performance record that gets them offered more studies, offered more complex studies, and offered studies with higher per-patient revenue. Sites with inconsistent or poor performance records receive fewer offers and are often limited to lower-complexity studies with smaller budgets.
The physician referral infrastructure is not just a recruitment tool — it is the mechanism through which a site builds the historical performance record that determines its long-term study portfolio.