The REF 2029 output eligibility period is the window during which a research output must first have been made publicly available in order to be submissible to the UK’s next Research Excellence Framework exercise. This is distinct from the general REF 2029 overview and from the assessment timetable itself — it specifically answers “which outputs count?”
The published date range
Per REF 2029’s Section 4 guidance on Contributions to Knowledge and Understanding (CKU) — the REF 2029 name for what REF 2021 called the “Outputs” element — outputs must be first made publicly available between 1 January 2021 and 31 December 2028 to be eligible for submission. This is the output eligibility period stated in the guidance published at 2029.ref.ac.uk.
“Publicly available” here follows REF’s established meaning: the date an output first became accessible in any form (for example, first online publication, first public dataset release, or first public performance/exhibition for practice-based outputs), not the date of a later formal version of record.
Confirmed vs. still provisional
This date range is stated in REF 2029’s published guidance modules, but research administrators should treat the broader REF 2029 guidance programme as still settling. REF 2029’s own guidance site notes that guidance modules are being finalised through 2026 and “may be subject to small revisions” as audit and submission guidance is completed. As of mid-2026, REF 2029 confirms that detailed audit and submission guidance has not yet been produced, and the programme has said a clearer picture of submission volumes will emerge once results of the 2027 Survey of Submission Intentions are available. In practice, that means the 1 January 2021 – 31 December 2028 window is the current, published position rather than a figure at risk of wholesale change, but institutions preparing REF 2029 returns should keep checking the guidance change log on 2029.ref.ac.uk rather than treating any one summary — including this one — as the permanent final word.
How this compares to REF 2021
REF 2021’s output eligibility period ran from 1 January 2014 to 31 December 2020, a seven-year window. REF 2029’s published window (2021–2028) spans eight years, reflecting the longer gap between the two exercises. For UK institutions, this means outputs first made available immediately after the REF 2021 census date are already inside the current REF 2029 eligibility window, well before the next exercise’s submission deadline.
No minimum per researcher, but a per-unit volume formula
A significant change from REF 2021: REF 2029 guidance states there is no minimum output requirement for individual staff members. Instead, the number of outputs a unit of assessment (UoA) submits is calculated at unit level — by multiplying a volume measure by 2.5 per UoA, then rounding to the nearest whole number (with .5 results rounding up). Guidance also notes that where a single researcher’s outputs make up more than five of a UoA’s submitted outputs, the submitting unit should explain that concentration within its statement of representation, rather than treating five as a fixed hard cap.
Delayed and reserve outputs
Two related provisions sit alongside the eligibility period:
- Delayed outputs: if an output has been accepted for publication but is not yet publicly available by 31 December 2028, a reserve output may be submitted in its place, covering outputs expected to become available between the submission date and the end of the publication period.
- Double-weighted outputs: a reserve output can also stand in if a request to double-weight a particular output is not approved.
Where the eligibility period sits within REF 2029 overall
CKU is one of three REF 2029 assessment elements, alongside Engagement and Impact, and Strategy, People and Research Environment (SPRE) — the renamed, restructured successor to REF 2021’s Environment element (previously piloted under the working name “People, Culture and Environment”). The output eligibility period covered on this page applies specifically to CKU; Engagement and Impact case studies and SPRE statements are governed by their own separate guidance and reference periods, not the output window described above.
Frequently asked questions
What is the REF 2029 output eligibility period?
Per REF 2029’s published Section 4 (CKU) guidance, it is 1 January 2021 to 31 December 2028 — the window in which an output must first have been made publicly available to be eligible for submission.
Is the REF 2029 eligibility period confirmed?
The dates are published in current REF 2029 guidance, but the wider guidance programme is still being finalised, with REF 2029 itself noting guidance modules may see small revisions and that detailed audit and submission guidance has not yet been produced. Treat the dates as the current published position, and check 2029.ref.ac.uk’s guidance change log for updates.
Is there a minimum number of outputs each researcher must submit?
No. REF 2029 guidance removes the individual minimum output requirement that existed under REF 2021. Output volume is instead calculated at unit-of-assessment level.
What happens if my output won’t be published before the eligibility window closes?
REF 2029’s reserve-output provision allows institutions to nominate a reserve output for outputs expected to become publicly available after the submission date but before the end of the publication period.
How does the REF 2029 eligibility period compare to REF 2021’s?
REF 2021 covered outputs first made publicly available from 1 January 2014 to 31 December 2020 (seven years). REF 2029’s published window, 1 January 2021 to 31 December 2028, spans eight years.
Related CASRAI resources
- REF 2029 (dictionary term) — general overview of the exercise, its structure, and assessment elements.
- REF 2021 — the prior exercise, for direct comparison.
- REF (Research Excellence Framework, UK) — what the framework is and does.
- REF impact case study — how the Engagement and Impact element works.
- What Is Research Excellence? — how institutions and funders define and assess research excellence more broadly.
- UKRI Funding — how UK Research and Innovation, a related but distinct UK research body, operates.
- Date of first open access — a related eligibility concept used in REF’s open-access compliance policy.
Sources: REF 2029 Section 4 guidance (Contributions to Knowledge and Understanding), REF 2029 guidance index, and REF 2029 FAQs, all published at 2029.ref.ac.uk, verified directly against the live site in July 2026.
