Recruitment Materials Are Not a Recruitment Strategy

What the new review actually found

The Cochrane review included randomized Studies Within A Trial, often called SWATs, in which recruitment methods were tested inside active trials. Of the 65 strategies identified, 49 had been evaluated in only one study. Costs were reported in just 17 of the 91 studies, retention in 15, and equity, diversity, and inclusion characteristics were poorly reported. Nearly all studies came from high-income countries. Those limitations matter because recruitment performance is highly dependent on the population, indication, protocol, and pathway through which people encounter a study. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42742038/))

Among the high-certainty findings, telephone reminders to people who had not responded to an initial postal invitation increased recruitment by an absolute 6 percentage points. Open-label trials recruited more successfully than blinded, placebo-controlled trials, although that is primarily a protocol-design consideration rather than something an individual site can change. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42742038/))

The findings receiving less attention may be more useful operationally. Adding multimedia information through a link or QR code to a paper information leaflet made little or no difference to recruitment or retention. User-tested information leaflets and advance recruitment letters also produced little or no improvement. These tools may still support understanding, accessibility, or consent quality, but teams should be cautious about assigning them enrollment forecasts they have not earned.

The gap between generating interest and enrolling a participant

Recruitment plans often emphasize the top of the funnel: impressions, clicks, referrals, registry matches, or records identified through database searches. Site workload begins after those numbers are generated. Every referral must be reviewed, contacted, documented, prescreened, scheduled, and, when appropriate, followed through consent and screening.

A referral source can look productive while creating little enrollment value. Fifty referrals that arrive without a working phone number, language preference, consent to contact, or basic eligibility information may require more coordinator time than ten well-qualified referrals. Conversely, a modest source can be valuable when people understand why they are being contacted and the site can respond quickly.

This is why recruitment reporting should distinguish reach from operational yield. At minimum, sponsors and sites should be able to see the following funnel stages.

• Potential participants identified or referrals received
• Records reviewed and suitable for contact
• Successful first contacts
• Completed prescreens
• Prescreen-eligible participants
• Appointments scheduled
• Appointments attended
• Consent discussions completed
• Participants screened, randomized, and retained
• Reasons for ineligibility, nonresponse, cancellation, and eligible decline

Follow-up should be a designed workflow, not coordinator improvisation

The telephone-reminder finding should not be interpreted as a universal instruction to call everyone repeatedly. The supporting studies involved people who had not responded to postal invitations, largely in settings with low initial recruitment. The practical lesson is narrower: passive outreach should have a defined transition to active follow-up, and that follow-up should be measured. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42742038/))

A separate 2026 study in a Chicago safety-net setting offers useful context. In a diabetes trial enrolling Black and Latine participants, in-person recruitment produced the highest enrollment rate, and two-thirds of enrolled participants joined after the first or second contact attempt. Latine participants and those with lower socioeconomic status were more likely to be recruited in person. This was one study in a specific population, so it should inform local testing rather than become a universal rule. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42392502/))

Before activation, each site should have an agreed contact protocol covering response time, number of attempts, spacing between attempts, permitted communication channels, language assignment, voicemail and text content, escalation rules, and the point at which a referral is closed. The site should then evaluate yield by attempt number. If the fourth and fifth attempts produce almost no completed prescreens, resources may be better placed elsewhere. If evening calls substantially improve contact, staffing should reflect that pattern.

Materials still matter, but they have a different job

A flyer or video can explain the study, support health literacy, prepare someone for a conversation, and help family members understand the commitment. Those are legitimate objectives. Problems arise when a material is expected to correct restrictive eligibility, frequent visits, delayed reimbursements, transportation barriers, an overburdened site team, or slow referral handling.

Recruitment content should therefore be evaluated against a specific purpose. Is it intended to generate awareness, help people determine basic relevance, reduce avoidable prescreen calls, explain randomization, or prepare participants for the visit schedule? Each purpose requires a different measure of success.

In multilingual markets such as South Florida and Puerto Rico, translation alone is not sufficient. The workflow must preserve language preference from the first inquiry through prescreening, consent discussions, visit reminders, and retention contacts. A Spanish-language advertisement followed by an English-only callback is not a bilingual recruitment process. It is a broken handoff.

Diverse recruitment requires capacity behind the channel

A recent qualitative study of diversity-focused recruitment interventions in U.S. cardiometabolic trials reached a similar operational conclusion. Community ambassadors, social media, and registry platforms helped some studies extend their reach, but implementation was constrained by limited staff time, funding, language access, transportation, eligibility restrictions, and institutional approval processes. Several participating teams also valued external recruitment support because they lacked the internal capacity to operate every channel effectively. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42566774/?utm_source=openai))

This distinction matters when sponsors evaluate sites serving historically underrepresented communities. Access to a population is not the same as funded capacity to recruit that population. Community relationships require staff time. Preferred-language follow-up requires qualified personnel. Evening availability affects staffing. Transportation and reimbursement processes need advance planning. None of these functions appear automatically because a site is located in a diverse community.

Feasibility should therefore ask how the recruitment workflow will be executed, not simply how many potentially eligible patients exist. CTTI’s recruitment recommendations similarly call for evidence-based feasibility, realistic metrics, adequate resources, appropriate site selection, and ongoing performance monitoring. ([ctti-clinicaltrials.org](https://ctti-clinicaltrials.org/wp-content/uploads/2021/06/CTTI_Recruitment_Recs_Recruitment_Planning.pdf))

A practical recruitment operating model for the next study

Sites and study teams do not need to abandon creative recruitment tactics. They need to place those tactics inside a disciplined operating system. Before enrollment begins, the sponsor, CRO, and site should agree on what data will be collected, who owns each handoff, how quickly referrals must be addressed, and when a channel will be changed or discontinued.

Recruitment reviews should focus on conversion and cycle time, not activity volume. A weekly meeting that reports 200 new leads but does not show time to first contact, prescreen completion, attendance, eligibility, and enrollment by source cannot identify the actual constraint. It may encourage more spending at the top of a funnel that the site does not have the capacity to process.

Finally, teams should consider embedding small, controlled recruitment evaluations within trials. CTTI recommends testing recruitment interventions and sharing both positive and negative findings. The Cochrane review makes clear why: the industry has many recruitment ideas, but relatively few have been replicated with strong evidence. ([pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/42742038/))

• Define the intended function of every recruitment channel and material.
• Establish contact standards before the first referral arrives.
• Track conversion, cycle time, effort, and cost by source.
• Review eligible declines and missed appointments for correctable barriers.
• Fund preferred-language outreach and human follow-up as operational work.
• Test local assumptions rather than importing performance claims from unrelated populations.
• Protect informed consent quality while working to improve recruitment efficiency.

The site-level takeaway

The strongest recruitment plan is rarely the one with the most channels. It is the one that connects an appropriate population, a feasible protocol, understandable information, timely human contact, and enough site capacity to complete the work.

The latest evidence should prompt a reset in how recruitment investments are evaluated. Better materials may support a better participant experience, but materials alone do not create responsiveness, trust, scheduling flexibility, or eligibility. Those outcomes come from the operating model behind the campaign.

For sponsors and CROs, the useful question is no longer simply, “What recruitment tools does this site have?” It is, “How does this site convert appropriate interest into an informed, completed screening process, and can the study support that workflow?”