A site wants to take on a study and projects strong enrollment. Before that projection becomes part of the recruitment plan, what gives sponsors and contract research organizations (CROs) the confidence the site can deliver?
Interest and enrollment estimates begin the evaluation, but establishing readiness means understanding which patients the site can reach and whether its team and facilities can truly support the protocol. Previous enrollment in similar studies offers some evidence, but the relevance of that evidence largely depends on how closely those studies resemble the current trial and what’s changed at the site since.
For sponsors and CROs, a reliable comparison connects patient access and enrollment history with investigator experience, staffing, and operational capacity. By testing the assumptions behind those factors, sponsors and CROs can choose sites that can genuinely support the study they’re planning.
Why site feasibility assessments need more than a questionnaire
A clinical trial site feasibility assessment evaluates whether a research site has the patient population, qualified personnel, processes, and resources to conduct a specific protocol and meet its operational requirements.
Positive questionnaire responses establish interest in a study, so during site identification and feasibility, it’s important to examine operational evidence of capacity to meet protocol demands alongside competing commitments. A site’s previous success may reflect staffing or resources that changed in the meantime.
In fact, the need for a broad, bulky questionnaire might be avoided altogether with data from reliable source systems, like enrollment records and current study activity. Still, when questions remain, one should focus site feasibility questionnaires on protocol-specific gaps to expedite an assessment.
Core clinical trial site feasibility assessment criteria
Patient access and population fit
Can this site reach enough eligible patients for the study?
To assess patient access and population fit, review relevant patient volume, referral pathways, geographic catchment area, competing studies, and alignment with key eligibility criteria.
A large patient population might yield relatively few eligible participants once prior treatments and disease characteristics enter the picture, so ask how the site arrived at its estimate and whether referral relationships can support recruitment during the enrollment window.
Enrollment performance and prediction
Review enrollment against targets, time to first patient (TTFP), screening outcomes, and withdrawals.
A missed target deserves investigation: Was the enrollment window shortened? Were eligibility criteria unusually restrictive? Has the site since changed its recruitment process? Strong historical results also need context before supporting a new projection.
(For more on this, check out Advarra’s site feasibility survey findings, which describe how sites approach questionnaires and where they experience burden.)
Investigator experience
How much time can the investigator commit to this study? Quantify that time commitment and expected level of engagement alongside actual therapeutic area experience and trial history.
Who will oversee study activities and handle decisions when the investigator isn’t available? Use delegation and coverage plans to figure that out.
Staffing and operational capacity
Evaluate coordinator workload, turnover, training, backup coverage, competing study load, and experience with required procedures.
Does the staffing plan depend on future hires? Who will perform the work, and how will study visits fit existing schedules? Keep any hiring uncertainty visible in the assessment, and when sponsor processes or technology requirements add work, think about opportunities for reducing burden on sites.
Facility, equipment, and process readiness
Facility readiness depends on how well the available space, equipment, pharmacy and laboratory arrangements, operating hours, and patient access support protocol-specific processes.
For example, as part of site feasibility and selection, one might confirm that trained operators are available to use specialized equipment specifically during required visit hours.
Using site feasibility assessment metrics to evaluate readiness and ability to deliver
Pair clinical trial site feasibility assessment metrics—including eligible patient counts, enrollment pace, and active study load—with qualitative context about workflow and staffing. An active study count becomes more informative when the site explains how coordinators divide their time across studies and where new visits would fit into existing schedules.
Site comparisons require consistent reporting periods and metric definitions, along with data from relevant therapeutic areas. Do patient figures represent screened, eligible, or enrolled participants? Confirm the starting milestone for TTFP as well so each result covers a comparable interval.
To modernize site feasibility and selection, weight assessment criteria according to protocol risk. If the protocol requires a specialized procedure, trained staff and suitable equipment may be readiness prerequisites for that. How do the supporting evidence, uncertainty about current capacity, and site-specific context affect the assessment? Make that reasoning explicit, and keep unresolved requirements visible alongside the score.
Past performance provides a relevant benchmark when studies have comparable indications, eligibility criteria, protocol demands, and enrollment windows, but differences in site populations, resources, and competing study commitments can help explain why enrollment performance differs across studies and sites, so account for these factors before drawing conclusions.
How to validate feasibility estimates and test assumptions
Sponsors and sites both make assumptions. A sponsor’s planned enrollment rate may depend on eligibility expectations that sites can’t support, while a site’s projection may assume referral access or staffing that’s still being arranged.
Site’s and sponsor’s expectations can be tested by using site feasibility questionnaires that guide operational discussions and focused follow-up questions like:
- How was patient availability estimated from current population data, and how were key eligibility criteria applied?
- How does documented enrollment on comparable studies support the proposed pace?
- Who will perform the required work within current staffing capacity?
- Where do projections differ from past performance, what’s changed, and what evidence supports the difference?
Relevant, current, direct evidence provides a stronger basis for decisions than self-reported estimates alone. Are examples, reported figures, documented results, and assumptions clearly labeled? Projected enrollment is a planning estimate, not a guaranteed outcome, so make sure they are.
And if protocol requirements, competing studies, staffing, or enrollment conditions change, revisit the assessment to confirm whether an earlier selection decision still holds despite the new circumstances.
Frequently asked questions about site feasibility assessments
Build a site selection process that’s easy to explain
When comparable metrics are combined with local context and evidence supporting the enrollment plan, a reliable assessment can clarify the basis for site selection and identify remaining uncertainty and follow-up needs.
By using a consistent process that adapts to each protocol’s demands, sponsors and CROs can reduce uncertainty and align patient access with operational capacity. Their selection decisions can then rest on comparable evidence and tested enrollment assumptions.
