Direct answer: Some do, most don’t, and the difference is usually invisible in the proposal. Inside most CROs, patient recruitment is a workstream owned by project management rather than a dedicated function: feasibility, site selection, and then an assumption that activated sites will enroll. When that assumption slips, the CRO either subcontracts a media vendor or brings in a recruitment partner. Finding out which version your CRO is running, before first patient in, is one of the higher-leverage questions a sponsor can ask.

What “recruitment” usually means inside a CRO

It means feasibility, site selection, startup, and then site-based enrollment. The CRO asks candidate sites what they can enroll, picks the ones with the best answers, activates them, and monitors what comes in.

Some large CROs do have a genuine in-house recruitment group with media buying, creative, and a call center behind it. Many don’t, and the plan quietly reduces to “the sites will handle it.” Both are legitimate products. The problem is that they’re described with identical language in an RFP, so sponsors routinely buy the second one believing they bought the first.

Where the CRO-led model works fine

Broad criteria, sites with deep patient databases in your indication, a quiet competitive landscape, and slack in the timeline. Sites enroll trials every day without help. If your study fits that description, adding a recruitment layer is cost without much return, and any honest recruitment company will tell you so.

Where it breaks, and it breaks in the same three places

Nobody owns the patient between interest and the site visit. A patient raises their hand, and the referral goes to a coordinator who already has forty open ones. That handoff window is where trials bleed, and in a standard CRO structure it belongs to no one in particular.

No fee is at risk against the enrollment number. Nearly 85% of interventional trials miss their enrollment milestones, and RFP responses overpromise enrollment timelines by 47% on average. Under most CRO contracts a late trial costs the sponsor money and bills the CRO more hours. That is not bad faith, it’s just what the incentives say.

Sites get treated as the only lever. When enrollment lags, the reflex is to add sites. The median site takes about 167 days to activate, so the fix lands well after the window it was meant to protect, and it doesn’t address whatever caused the first cohort of sites to underproduce.

Why CROs bring in a recruitment partner

This is less adversarial than sponsors assume. CROs are usually the ones who initiate it, for reasons that are entirely rational:

• Speed without headcount. Standing up compliant patient-facing media, screening, and follow-through is a staffing problem a CRO doesn’t want to solve mid-study.
• Risk transfer. A success-based partner absorbs enrollment risk the CRO cannot price into a fixed-fee contract.
• Protecting the client relationship. Enrollment misses land on the CRO’s account team long before they land anywhere else.
• Media buying is a specialist muscle. Running paid social to patient populations, at scale, within regulatory and IRB constraints, is not a project management skill and shouldn’t be treated as one.
• Sites are happier. Pre-qualified, double-screened referrals reduce site burden instead of adding to it, and sites remember which partner sent them work that converted.

We work this way in both directions. Sometimes the sponsor contracts us and we coordinate with their CRO. Sometimes the CRO is the contracting party and we sit underneath them. The operating model is the same either way, and so is the pricing: we’re paid on enrolled patients.

What a good CRO and recruitment partnership actually looks like

• One shared funnel view, site level, updated weekly, that both parties read from
• A clean ownership boundary. The CRO owns the trial and the site relationships. The recruitment partner owns the patient path from first click to the site door.
• Referrals that arrive double-screened, scheduled, and with records retrieved where possible, rather than raw form fills forwarded to a coordinator
• The recruitment partner’s fee tied to enrollments, so a miss costs them too
• A named escalation path for site-level blockers, because most of them are logistical and fixable

For context on what that produces: our web screener removes about 60% of applicants and the phone screen removes another 77% of those remaining, which is why 89% of the patients we walk into a site go on to sign the consent form.

The honest caveat

If your CRO has a real in-house recruitment function, with dedicated media buying and site-level conversion reporting, a third party can add coordination cost without adding much capability. There’s a simple test. Ask them to show you the funnel from a comparable program: referrals, screens, consents, randomizations, by site. If they can produce it, they’re running the real thing and you may not need us. If the answer is a reach number or a pause, you have your answer about that too.

Frequently asked questions