ARO or CRO: what’s the difference in clinical research?

the difference in clinical research

where the terms can be confusing: overlap is real

It’s normal to see overlap in services. An ARO can provide operational delivery, and a CRO can employ deep therapeutic expertise and run highly scientific programmes. The practical difference is often less about what they can do, and more about how they’re set up to do it—including governance, resourcing, process standardisation, and contracting structure.

A helpful lens is:

• CRO describes a sponsor-contracted outsourcing relationship recognised in GCP. admin.ich.org

• ARO describes an academic/not-for-profit operating context providing one or more trial functions. Research Roadmap+1
  
  

typical roles across the trial lifecycle

Below are common workstreams supported by either AROs or CROs.

study planning and start-up

• feasibility and site selection support

• operational input into protocol design

• contracts and budgets

• ethics/regulatory submissions (where applicable)
  
  

trial conduct

• project management and vendor coordination

• site activation support

• monitoring and issue management

• quality processes and audit/inspection readiness
  
  

data to evidence

• data management, cleaning, database lock

• biostatistics and reporting

• safety data handling and reconciliation

• endpoint/event processes (where used)

governance and accountability under GCP

GCP gives very clear principles relevant to CRO involvement:

• the sponsor may transfer any or all trial-related duties and functions to a CRO, but

• ultimate responsibility for trial quality and data integrity remains with the sponsor European Medicines Agency (EMA)+1

• duties transferred should be specified in writing, and anything not transferred remains with the sponsor admin.ich.org
  
  

In practice, this is why well-run trials emphasise:

• clearly defined scope and responsibilities

• oversight plans and escalation paths

• documentation of quality control and decision-making
  
  

These governance principles apply regardless of whether the operational partner is an ARO-type or CRO-type organisation.

how AROs and CROs often work together

Many programmes use a hybrid model, for example:

• academic/ARO-style leadership for scientific direction, investigator engagement, and academic networks, alongside

• CRO delivery for execution-heavy workstreams (e.g., multi-country operations, monitoring coverage, integrated project controls)

This model is common because modern trials often need both scientific leadership and repeatable operational execution.

closing thoughts

If your primary goal is to anchor a study in an academic ecosystem with investigator-led governance, an ARO model may be a natural fit. If your goal is to outsource defined trial duties to a delivery partner under a sponsor contract—especially when you need scalable operational capacity—then a CRO model is typically how that relationship is structured in GCP.

If you’re exploring what this looks like in cardiovascular research, we’re happy to share how we typically structure responsibilities, oversight, and delivery models as a cardiovascular-focused full-service CRO.