An Institutional Review Board (IRB) and a Research Ethics Committee (REC) both review research involving human participants before it can start, but they sit inside different legal systems. An institutional review board operates under the US Common Rule (45 CFR 46) and FDA regulations (21 CFR Parts 50 and 56); a REC operates under the UK’s Health Research Authority (HRA) and the Integrated Research Application System (IRAS). For research offices running multi-country studies, the terms are related but not administratively interchangeable.
An institutional review board is a US-based committee, affiliated with a specific institution, that reviews, approves, and monitors research protocols involving human subjects to ensure risks are minimised and consent is properly obtained.
- What is an IRB, and what is a REC?
- How does IRB review work under the US Common Rule and FDA rules?
- How does REC review work under the UK’s HRA and IRAS system?
- IRB vs REC: what differs for research offices working across both systems?
- Related terms: IEC, IBC, and ERB explained
- Answer-first Q&A
- Implications for research offices
What is an IRB, and what is a REC?
An institutional review board (IRB) is a US committee, established by a university, hospital, or other institution, that reviews proposed and ongoing research involving human subjects for ethical and regulatory compliance. A Research Ethics Committee (REC) is the UK equivalent term, used most formally for the National Health Service (NHS) research ethics committees recognised by the Health Research Authority.
Both bodies exist to apply the same underlying ethical principles — informed consent, risk minimisation, equitable participant selection — but they were codified through separate national histories. The US system traces to the National Research Act 1974 and the 1979 Belmont Report, which established the IRB requirement now embedded in the Common Rule. The UK system developed through NHS research governance frameworks and was consolidated under the HRA, established in 2015 under the Care Act 2014.
How does IRB review work under the US Common Rule and FDA rules?
US human-subjects research is governed by the Common Rule, formally 45 CFR 46, which applies to federally funded research across most institutions, and by FDA regulations (21 CFR Parts 50 and 56) for FDA-regulated clinical investigations. Institutions maintain their own IRBs, registered with the Office for Human Research Protections, rather than relying on a single national body.
Under 45 CFR 46.107, each IRB must have at least five members with varying backgrounds, including at least one scientist, one non-scientist, and one member unaffiliated with the institution. Reviews fall into three tracks:
- Exempt review — minimal-risk research meeting specific regulatory categories, such as anonymous surveys or secondary analysis of existing data.
- Expedited review — minimal-risk research falling into defined categories, reviewed by one or more designated members rather than the full board.
- Full board review — research involving more than minimal risk to participants, requiring a convened meeting.
The 2018 revision to the Common Rule (effective 21 January 2019) introduced a mandatory single IRB of record for multi-site cooperative federally funded research, replacing the older model in which every participating site obtained its own separate approval.
How does REC review work under the UK’s HRA and IRAS system?
UK research involving NHS patients, staff, tissue, or data must obtain HRA Approval, a combined ethics and research-governance decision that the Health Research Authority has issued since 2016, replacing the previous split process of separate REC opinion and local NHS permission. Applications are submitted once through the Integrated Research Application System (IRAS), a single online portal covering ethics, regulatory, and governance information.
Under the HRA’s Governance Arrangements for Research Ethics Committees (GAfREC), each NHS REC must include a minimum membership with at least a third drawn from lay (non-expert) members, ensuring the committee is not composed solely of clinicians or researchers. This lay-majority-influenced structure is a distinct emphasis compared with the smaller five-member US minimum.
Crucially for research administrators, “REC” in the UK does not always mean an HRA-recognised body. University and institutional research ethics committees also use the REC label for non-NHS academic research — social sciences, humanities, non-clinical studies — and these operate independently of HRA recognition, set their own membership rules, and are not accessed through IRAS. This two-tier structure (HRA-recognised NHS RECs vs institutional RECs) is the UK’s functional analogue to the US system of institution-based IRBs, and it is a distinction that generic “IRB vs REC” explainers frequently collapse into one category.
IRB vs REC: what differs for research offices working across both systems?
The table below summarises the operational differences a research office needs when routing a protocol through both jurisdictions.
| Feature | US: Institutional Review Board (IRB) | UK: Research Ethics Committee (REC) |
|---|---|---|
| Governing framework | Common Rule (45 CFR 46); FDA 21 CFR 50/56 | HRA Approval; UK Policy Framework for Health and Social Care Research |
| Coordinating body | Institution-based; overseen by OHRP/FDA | Health Research Authority (NHS RECs); institutions (non-NHS RECs) |
| Application route | Institution-specific submission systems | Single portal: IRAS |
| Minimum membership | 5 members (§46.107) | Larger board; at least one-third lay members (GAfREC) |
| Multi-site studies | Single IRB of record mandated since 2019 for cooperative federal research | Single HRA Approval covers all NHS sites in England |
| Review tiers | Exempt / expedited / full board | Proportionate review for lower-risk NHS studies |
Two further practical differences matter for cross-border protocols. First, US IRB fees are common for commercially sponsored trials reviewed by independent (non-institutional) IRBs, whereas HRA REC review carries no charge to applicants. Second, UK RECs assess proposals against UK GDPR, which imposes stricter consent and data-subject-rights requirements than the US HIPAA Privacy Rule that IRBs typically reference alongside the Common Rule.
Related terms: IEC, IBC, and ERB explained
Research offices encounter several adjacent terms that are not synonyms for IRB or REC:
- Independent Ethics Committee (IEC) — the term used internationally, particularly in pharmaceutical/industry-sponsored trials, for a committee not affiliated with a single institution. ICH E6(R2/R3) Good Clinical Practice guidance uses “IRB/IEC” as its umbrella phrase precisely because national terminology varies.
- Institutional Biosafety Committee (IBC) — a separate US committee (required under NIH Guidelines) that reviews recombinant/synthetic nucleic acid and biosafety risk, not human-subjects ethics; a protocol can require both IRB and IBC review.
- Ethical Review Board (ERB) or Research Ethics Board (REB) — generic or Canadian-context synonyms for the same function as an IRB or REC.
Answer-first Q&A
Is an Institutional Review Board an ethics committee?
Yes. An Institutional Review Board is functionally a research ethics committee operating under US federal regulation. It reviews and approves human-subjects research protocols, monitors ongoing studies, and can require modifications or suspend approval — the same core function performed by RECs, IECs, and REBs in other jurisdictions under different national names.
What is the difference between an independent ethics committee and an Institutional Review Board?
An Independent Ethics Committee (IEC) is not tied to a single institution and commonly reviews industry-sponsored trials across multiple sites, particularly outside the US. An IRB is institution-affiliated by definition. In practice, both terms describe the same regulatory function and are used interchangeably in ICH GCP guidance.
What is the difference between IRB and IBC?
An IRB reviews the ethics of research involving human participants. An Institutional Biosafety Committee (IBC) reviews biosafety risks of recombinant DNA and other biological materials under NIH Guidelines. They are separate committees with separate remits; a single study can require sign-off from both.
What types of people must be present at an institutional review board?
Under 45 CFR 46.107, a US IRB must include at least five members with varied backgrounds: at least one member whose expertise is primarily scientific, one whose expertise is primarily non-scientific, and one member not otherwise affiliated with the institution, to ensure independent, non-institutional perspective on risk to participants.
Implications for research offices
Research administrators managing protocols that span both countries should treat “IRB” and “REC” as related but non-substitutable regulatory terms, not as translation equivalents to drop into a single template. A US sponsor cannot rely on IRB approval to satisfy HRA Approval requirements for NHS sites, and a UK REC opinion does not substitute for FDA IRB oversight where FDA-regulated products are involved.
As international collaboration grows, research offices increasingly need staff who can map both systems: the single-IRB-of-record model under the revised Common Rule, and the single-HRA-Approval model via IRAS. Building that literacy into onboarding and protocol templates reduces duplicated submissions and approval delays on cross-border studies.
For related standards used by the same research offices, see CASRAI’s research administration resources and the CASRAI Dictionary for further terminology.
