In clinical trial outsourcing, sponsors choose between two main models: Functional Service Provision (FSP) and Full-Service Outsourcing (FSO). Choosing between FSP and FSO depends on your clinical trial's needs and objectives. By evaluating your resources, desired level of control, and the specific demands of the trial, you can select the outsourcing model that best supports your aims.
In practice, many sponsors use one model as a default and adapt by study or function as needs change. Outsourcing approaches have also shifted over recent years, with increased use of FSP and hybrid approaches as sponsors face increasingly competitive talent markets. Mixing of service models can also support time efficiencies that help bring therapies to market faster.
What is full-service outsourcing (FSO) in clinical trials?
Full-Service Outsourcing (FSO) involves handing over the entire management of a clinical trial to a CRO. This model offers simplicity and a single point of contact, appealing to sponsors who prefer to outsource all trial aspects. However, FSO can be more expensive and less flexible, potentially limiting the sponsor's control over specific trial components and overall strategy.
It’s also common for 'full service' arrangements to include carve-outs where the sponsor retains specific strategic or specialist elements.
What is the difference between FSP and FSO?
The practical differences between FSP and FSO usually come down to accountability, governance, and flexibility.
With FSO, sponsors typically look for a single integrated delivery approach and clearer end-to-end accountability. With FSP, delivery is split by function and the sponsor usually retains more direct control of priorities and cross-functional integration.
FSO is also most often delivered using the vendor’s systems and standard operating procedures (SOPs), whereas FSP often operates within the sponsor’s systems and SOPs.
FSO is typically overseen by a CRO project manager, while FSP is often overseen by an insourced project manager. Commercially, FSO contracts are commonly milestone or unit-based, whereas FSP contracts are often full-time equivalent (FTE) or unit-based.
FSP can increase sponsor-side governance because there are more interfaces to manage. FSO can reduce interfaces, but it still needs active oversight to keep delivery aligned to sponsor intent.
In either model, alignment on reporting and issue management matters, especially where multiple parties are involved. Where sponsors leverage multiple models, they may also be able to track KPIs and KQIs across models, using comparative visibility to support decision-making and process improvement.
We have summarised these differences in the table below:
| Dimension | FSO (Full-Service Outsourcing) | FSP (Functional Service Provision) |
| Delivery model | Single integrated delivery approach | Delivery split function |
| Accountability | Clearer end-to-end accountability | Sponsor retains more direct control of priorities and cross-functional integration |
| Sponsor control | Potentially less control over specific components and overall strategy | More direct control of priorities and integration |
| Governance / interfaces | Fewer sponsor-managed interfaces, but still needs active oversight | More interfaces to manage → increased sponsor-side governance |
| Flexibility | Can be less flexible | Often more flexible within functions |
| Systems & SOPs | Typically delivered using the vendor's systems and SOPs | Often operates within the sponsor's systems and SOPs |
| Oversight | Typically overseen by a CRO project manager | Often overseen by an insourced project manager |
| Commercial model | Commonly milestone or unit-based | Often FTE or unit-based |
| Reporting / issue management | Alignment matters, especially where multiple parties are involved | Same — alignment matters, especially where multiple parties are involved |
| Cross-model performance tracking | If using multiple models, KPIs/KQIs can be compared across models | If using multiple models, KPIs/KQIs can be compared across models |
When should you use FSP vs FSO in clinical trial outsourcing?
The decision is usually less about labels and more about what you need to optimise; control, capacity, speed of scaling, accountability, and the amount of coordination you can realistically sustain. Another consideration is the access to talent that you may gain from the partnership with the vendor CRO, in some setups, the value is less the model itself and more the ability to plug in hard-to-find expertise as an extension of internal teams.
FSP can be a better fit when:
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You need functional capacity but want to keep day-to-day priorities close to the sponsor.
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You need flexibility to scale resourcing within a function as workload changes across the portfolio.
- You can support the governance needed to manage multiple interfaces.
- You need faster mobilisation, with dedicated roles or mechanisms to ramp up delivery quickly.
FSO can be a better fit when:
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You want consolidated delivery with fewer sponsor-managed interfaces.
- Accountability for cross-functional delivery needs to sit clearly with one partner.
- You have limited bandwidth to coordinate across multiple vendors and handoffs.
What governance and integration risks should sponsors plan for?
In functionally split models (FSP and many hybrids), governance and interfaces often drive delivery risk.
Common risks to plan for include:
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Unclear ownership at interfaces, leading to delays or duplicated effort.
- Underestimated sponsor governance load.
- Misaligned reporting and escalation routes.
Mitigation starts with clear ownership, escalation, and integrated oversight. If you're implementing an FSP or hybrid approach, it's worth being aware of the important considerations to plan for.
What do cost, scale, and switching considerations look like in FSO vs FSP?
Total cost depends on portfolio scale and transition effort, not just the model label.
Some FSP economics assumptions depend on having enough volume to realise efficiencies across a programme. For smaller portfolios, the economics may be less compelling once sponsor governance effort is included.
Changing models can introduce switching costs through onboarding,process alignment, and rebuilding interfaces.
Can you combine FSO and FSP in a hybrid model?
Yes. Hybrid approaches are also common, combining a largely full-service setup with targeted functional augmentation to balance integrated end-to-end delivery with targeted flexibility.
In hybrid setups, partner experience across both FSO and FSP can matter, because combining models often requires active tailoring and integration.
Common patterns include:
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Using full service for overall trial delivery while adding FSP support for specific specialist functions.
- Splitting by geography where operational needs differ.
- Varying the model by phase, therapeutic area, or delivery complexity.
- Incorporating FSP resources into FSO studies when specific key roles (e.g. project managers, CRAs, statisticians, or medics) or study components are desired.
The practical benefit is targeted flexibility whilst the consideration is increased interface management.
Need support deciding between FSO and FSP, or shaping a hybrid outsourcing approach for your clinical programmes?
Quanticate works with sponsors to define the right scope, resource critical functions, and set clear interfaces and governance that support reliable delivery. Request a consultation and a member of our team will be in touch.
