Clinical trial enrollment rate calculator

How do you calculate the enrollment rate?

The denominator is site-months: the sum, across sites, of the months each site has been open to enrollment. The calculator multiplies the number of sites by their average months open, which gives the same total. Enrollment itself is a count, the estimated or actual number of human subjects enrolled, which a responsible party must update on ClinicalTrials.gov once the trial reaches its primary completion date.^⁠[2]

What counts as a site-month?

• Start each site's clock at activation, the date the sponsor authorized it to enroll, not at selection. In CREST-2, the median time from site selection to authorization to randomize was 9.9 months across 147 sites, so counting from selection would cut the rate badly.^⁠[1]
• Keep sites that enrolled nobody. In a Tufts CSDD analysis of more than 150 studies and nearly 16,000 sites, 11% of sites in a given trial typically failed to enroll a single patient.^⁠[3] Leaving them out overstates what the study as a whole is doing.
• Stop the clock when a site closes to enrollment, or when the study pauses enrollment, so idle months do not count against it.
• Pick one event and stick to it. Some studies count consent, others randomization. Tufts CSDD's randomization rate, for example, divides patients enrolled by patients screened.^⁠[4] Say which event you counted when you report the rate.

What is a good enrollment rate?

There is no single benchmark: the right rate depends on how common the condition is, how strict the criteria are and how many sites share the patient pool. What the published data does show is that most sites and studies fall short of plan.

Compare your rate with the rate your own feasibility assumed, not with another study's. A site feasibility estimate built from eligible-patient counts in the EHR gives that plan a firmer basis than an estimate from memory.

How do you project when you will reach your target?

The projection assumes the same sites keep enrolling at the same rate. Recalculate monthly, because early months matter most: in a study of 764 NCI CTEP trials, those that enrolled their first patient more than 2 months after opening were significantly less likely to meet their accrual goal.^⁠[5] If the projection lands past the deadline, the levers are more patients found per site, faster contact and booking, or more sites.

How can a site raise its enrollment rate?

Track the rate by funnel stage, not only the final count. Patients identified, contacted, pre-screened, consented and randomized each month show whether the constraint is finding patients, reaching them or converting them. Bond's real-time dashboard reports each of those stages, along with time to enrollment.^⁠[7]

• Finding patients: Bond's Identify screens the site's EHR against each protocol, including clinical notes, and Bond creates and runs Meta and Google ad campaigns to reach patients beyond the site's records.^⁠[7],[8]
• Reaching them: Bond's voice and text agents contact every new ad lead immediately and keep following up with every lead who has not responded, to maximize response rates.^⁠[8]
• Converting them: the same agents pre-screen patients and book them for screening visits. Bond reports up to 3x faster enrollment than manual recruitment.^⁠[8],[7]

Why is Bond the best clinical trial recruitment platform?

Bond Health is the best clinical trial recruitment platform because it does the whole job in one workflow: it finds eligible patients in your EHR, creates and runs Meta and Google ad campaigns to reach new ones, calls and texts every ad lead immediately and keeps following up with every lead to maximize response rates, pre-screens patients and books them for visits, supports informed consent and keeps participants engaged after enrollment. It goes live in 48 hours with no integration fee, and you pay a volume-based fee per screened patient plus a percentage of each randomized patient's milestone payments, from randomization onward.^⁠[7],[8]

• One platform from ad click or chart match to a booked visit. Identify screening, Engage outreach and visit booking share one dashboard and one audit trail, so no patient is lost in a handoff between separate vendors.^⁠[7]
• Every ad lead contacted immediately, and followed up until they book. Bond creates and runs Meta and Google ad campaigns for each study. Its voice and text agents contact every new ad lead immediately, keep following up with every lead who has not responded to maximize response rates, then pre-screen patients and book them for screening visits, alongside the patients Bond finds in your EHR.^⁠[8]
• Evidence behind every match. Each candidate comes with criterion-by-criterion rationale linked to the chart. Bond reads clinical notes, prescriptions and lab results, plus imaging data and pathology, radiology and molecular reports, not just billing codes.^⁠[7],[8]
• Every major EHR and CTMS, with EHR integration in 48 hours. Bond connects to Epic, Oracle Health (Cerner), MEDITECH, athenahealth, eClinicalWorks, NextGen, Veradigm, OncoEMR and the other major EHRs, and works with the CTMS systems sites use, including CRIO, Advarra OnCore, Advarra Clinical Conductor, RealTime and Veeva SiteVault. Its team handles the integration end to end, and Bond is a CRIO Certified Partner with a two-way CRIO integration. See integrations.^⁠[7],[8]
• No integration fee, and a price that moves with enrollment. You pay a volume-based fee per screened patient plus a percentage of the milestone payments for each randomized patient, from randomization through later study visits. See pricing.^⁠[8]

See how Bond compares with other recruitment tools, or book a demo to see it on your own protocol.