Outsourced Clinical Trials: Outsource the Work, Not the Responsibility

A 2015 industry forecast expected about 72% of clinical trials to be run by CROs by 2020 [1]. The work moves to a CRO and to the vendors the CRO hires in turn, yet regulators still hold the sponsor responsible for participant protection and data reliability. A sponsor can transfer tasks but not that responsibility, so choosing a model changes who runs the project, not who answers for it. The oversight you keep down the vendor chain is what matters, and a weak arrangement shows first at enrollment, where the decision about who owns site selection is made before the vendor starts. Refero does not run recruitment campaigns. We vet and match the clinical research marketing agencies that do, so what follows is written for the buyer, from what those vendors need and see.

Outsourced clinical trials at a glance

Sponsors have long outsourced a large share of trial work, and the published evidence suggests the risk it leaves with the sponsor is most visible at enrollment.

• A 2015 forecast expected about 72% of clinical trials to be performed by CROs by 2020; it is a forecast rather than a measured share [1]
• A CRO's own 2017 analysis, reported second-hand, put outsourced clinical development nearer 64% [2]
• In a 2018 CRO-run survey, 68% of sponsors said they were much more likely to hire a vendor than five years earlier [3]
• Only 45.9% of surgical randomized trials in one analysis met their enrollment target [4]
• Only 20.4% of those trials finished within their planned timeframe [4]

How outsourced clinical trials work: four models

Outsourced clinical trials are trials in which a sponsor contracts a CRO or specialist provider to run part or all of the work and transfers defined activities in writing, while the sponsor keeps ultimate responsibility for participants and data [5]. Four models cover most arrangements, and they differ in who runs the project and how much oversight work lands on the sponsor's own team.

Four outsourcing models compared by who runs the project and what the sponsor keeps.

Sponsors choose among these models for access to expertise, established sites and flexible capacity, and the table shows that no model removes the sponsor's own work; it only changes where that work lands. The 68% in the 2018 CRO-run survey measures intent to hire more vendors rather than reliance on them, and a CRO surveying its own customers gives a directional signal rather than a neutral measure [3].

What the sponsor keeps when a clinical trial is outsourced

A sponsor can transfer trial activities to a CRO in a written agreement, but the ultimate responsibility for participant protection and data reliability stays with the sponsor. ICH E6(R3) says so for service providers generally [5]. FDA's rule for INDs, 21 CFR 312.52, lets a sponsor transfer obligations to a CRO only if the transfer is described in writing, treats any obligation the writing does not cover as not transferred, and holds the CRO to the regulations for what it assumes [6]. FDA's sponsor-oversight training puts the same idea in two lines: sponsors can delegate tasks to third parties but cannot delegate responsibilities [7].

Duties a sponsor can transfer in writing against duties that stay with the sponsor.

Oversight is a set of concrete duties that follow the same transfer, and each one can be checked in the contract.

Qualify the provider before you award the work

ICH E6(R3) makes the sponsor responsible for assessing whether a service provider can perform the transferred activities [5]. FDA's sponsor-oversight materials ask whether site selection visits or vendor audits before signing, plus a data audit at the end, are enough for the tasks delegated, which treats a pre-award audit as a recognized control whose depth depends on the tasks [7].

List the transferred duties in a written agreement

The agreement should name each activity that moves, because ICH E6(R3) expects transferred activities to be documented and agreements to be in place before the activities start [5]. Anything the agreement leaves out is treated as retained by the sponsor [6], so a vague contract leaves duties with the sponsor by default.

Keep access to SOPs and performance metrics

ICH E6(R3) says the sponsor should have access to relevant information, such as SOPs and performance metrics, for selecting and overseeing providers [5]. Without that access, a sponsor finds out about a problem only when the CRO chooses to report it.

Review by risk and keep reviewing

FDA's risk-based monitoring guidance asks sponsors who delegate monitoring to a CRO to keep evaluating the CRO's performance after qualification and throughout the study, for example through monitoring reports and quality metrics [8].

Follow the work down the vendor chain

When a CRO hires its own vendors, oversight follows the work. FDA's inspection program for sponsors and CROs covers contractors, subcontractors and vendors to whom services are outsourced, and inspectors check how the sponsor selected the CRO and what criteria it used [9]. European regulators say contracts should let the sponsor audit both the CRO and its subcontractors [10]. Both point the same way: the sponsor's oversight has to reach past the CRO to the vendors doing the work.

This is not legal advice; confirm requirements with regulatory counsel and the IRB of record.

Deciding what to outsource by function, phase and trial type

Whether to outsource a function depends on three inputs: whether the in-house team has the capacity and skill, how complex the function is for this protocol, and when it is needed. Run each function through two questions: whether to keep it or outsource it, and how you will oversee it.

• Monitoring: outsource if the team cannot cover sites in several regions; oversee through monitoring reports and metrics [8].
• Data management: outsource through a functional service provider if you want your own processes; oversee through access to records [5].
• Recruitment: outsource to a specialist if sites cannot reach enough patients; oversee through enrollment reports and IRB-reviewed materials [11].
• Vendor oversight itself: keep in house, because it cannot be transferred [5].

Phase changes the answer. A five-person team running a first Phase II often takes full-service support or a hybrid of data management plus one specialist, because it lacks the people to manage separate vendors. A global pivotal study usually has more to coordinate, so it needs a stronger in-house oversight owner whichever model is chosen. Trial type matters where the work differs: a device or diagnostic study may need specialist regulatory and site support that a drug-focused provider lacks.

Full-service CROs or specialists: who runs outsourced clinical trials

The largest full-service CROs offer one contract and a broad range of services, while specialists take a single function to the sponsor's or CRO's specification. For a small sponsor the trade-off is attention: a large full-service CRO brings scale and established processes, yet a small study can sit lower in its priorities. A specialist focuses on one function, but the sponsor or CRO must integrate it, and the sponsor still owes oversight of it [5].

Ask each shortlisted provider who will manage your study day to day, which activities it subcontracts and to whom, what metrics it reports and how often, and what happens when it misses a milestone.

Remote trial elements bring in new vendor types, and readers who want those categories and the evidence behind them can use the decentralized trials guide. Each new vendor adds a link to the chain, and the sponsor has to qualify it.

Why outsourced trials slip at enrollment

Enrollment is where an outsourcing decision is most exposed to delay, because the vendor inherits the protocol and the sites chosen before it starts [13]. The published shortfall data show how common the problem is, though not how much a vendor changes it: in an analysis of surgical randomized trials, fewer than half met their enrollment target (45.9%), and among those that fell short the median shortfall was 31.0% of the planned sample size [4].

Handing recruitment to a vendor helps but does not repair that inheritance. FDA's guidance on enrolling representative populations points to eligibility criteria, enrollment practices and trial design as levers [13], and a vendor cannot widen a restrictive protocol or add sites that were chosen poorly. The decision that most often delays enrollment is therefore the one made before the vendor starts: who owns site selection and feasibility, and on what evidence. The patient recruitment benchmarks show how site capacity and eligibility drive timelines.

If recruitment is outsourced as a single function, keep prescreening and consent distinct. FDA treats direct advertising for subjects as the start of the consent process and expects IRB review of recruitment materials and procedures [11][12], yet prescreening by phone under an IRB-reviewed script is not informed consent, and informed consent still happens at the site. In a common workflow, the vendor passes qualified referrals to the site after such a script, though FDA does not require every vendor to work that way.

Before you sign: contract moves for outsourcing clinical trials

Contract terms decide whether oversight is possible, so make these three moves before signing, and each one has its own trigger.

Write the subcontractor list and audit rights into the agreement

Use this if the CRO plans to use vendors you have not qualified. Ask for the list of subcontractors, flow-down terms (the clauses that pass your requirements on to each subcontractor) fitted to each role, and the right to audit those subcontractors, because regulators expect oversight to reach activities a provider passes on [5][10].

Set enrollment metrics, a reporting cadence and a remedy

Use this if the CRO owns site selection and feasibility. Name the metrics (sites activated, patients screened and patients randomized), how often they are reported and what happens when targets slip, such as a recovery plan or a review of site choices.

Keep one in-house owner for vendor oversight

Use this if the team is too lean to review every vendor in depth. The in-house owner tracks performance metrics, open issues, subcontractor changes and escalations against the written agreement, so the oversight file exists before an inspector asks for it [5][9].

If you would rather not run that evaluation alone, Refero screens healthcare marketing and patient recruitment agencies against five published criteria and introduces up to three that fit your brief. It is free for buyers, and there is no obligation to hire anyone we introduce. Tell us what you need.

Frequently asked questions

What are the main types of clinical trial outsourcing?

Full-service outsourcing gives a CRO the whole project. A functional service provider supplies staff for specific functions under the sponsor's management, hybrid models split functions between vendors, and single-function specialists take one slice of work. The four models differ in who runs the project and what the sponsor keeps.

Is the sponsor still responsible if the CRO makes a mistake?

Yes. Activities can be transferred in writing, but ultimate responsibility for participant protection and data reliability cannot [5][6]. At inspection FDA looks at how the sponsor selected and oversaw the CRO, so oversight records matter as much as the contract [9].

What are the current trends in clinical trial outsourcing?

The clearest sourced trend is regulatory: ICH E6(R3) expects more explicit sponsor resourcing for oversight [14]. Older figures show outsourcing growing, with a 2015 forecast of about 72% of trials and a 2018 survey in which 68% of sponsors said they were much more likely to hire a vendor than five years earlier [1][3], but they describe earlier years and should not be read as current shares.

Why do so many clinical trials fail or run late?

Enrollment is a common cause. In one analysis of surgical randomized trials, only 20.4% finished within their planned timeframe [4]. Eligibility criteria, enrollment practices and trial design are the levers FDA identifies, so a recruitment vendor helps most when the protocol and sites are sound [13].

Is outsourcing clinical trials legal in the US?

Yes. FDA rules let a sponsor transfer obligations to a CRO if the transfer is described in writing, and the CRO becomes subject to the same regulatory action as a sponsor for failing to comply with what it assumes [6]. Responsibility for oversight of the work stays with the sponsor [7].

Sources

• Clinical Services Market Poised For Growth (citing JZ Med forecast). PharmaVoice, 2015. Link
• The shifting roles of CROs. World Pharmaceutical Frontiers, 2024 (reporting a CRO's own 2017 analysis). Link
• DeArment, A. Survey highlights drugmakers' CRO needs as demand for services grows. MedCity News, 2018. Link
• Shadbolt C, Naufal E, Bunzli S, et al. Analysis of Rates of Completion, Delays, and Participant Recruitment in Randomized Clinical Trials in Surgery. JAMA Network Open, 2023. Link
• International Council for Harmonisation. Guideline for Good Clinical Practice E6(R3), Step 4. ICH, 2025. Link_Step4_FinalGuideline_2025_0106.pdf)
• Code of Federal Regulations. 21 CFR 312.52: Transfer of obligations to a contract research organization. eCFR. Link
• US Food and Drug Administration. Session 1: Sponsor Oversight in Clinical Trials. FDA. Link
• US Food and Drug Administration. Oversight of Clinical Investigations: A Risk-Based Approach to Monitoring. FDA. Link
• US Food and Drug Administration. Compliance Program 7348.810: Sponsors, Contract Research Organizations and Monitors. FDA. Link
• European Medicines Agency. Q&A: Good clinical practice (GCP). EMA. Link
• US Food and Drug Administration. Recruiting Study Subjects. FDA. Link
• US Food and Drug Administration. Informed Consent: Guidance for IRBs, Clinical Investigators, and Sponsors. FDA. Link
• US Food and Drug Administration. Enhancing Participation in Clinical Trials -- Eligibility Criteria, Enrollment Practices, and Trial Designs: Guidance for Industry. FDA, December 2025. Link
• ACT EU. Workshop report on ICH E6(R3). European Union. Link