The ARRIVE guidelines (Animal Research: Reporting of In Vivo Experiments) are the reporting checklist for publishing studies that use live animals. The current version, ARRIVE 2.0, sets out 21 items a manuscript should cover so that readers, peer reviewers, and anyone attempting to replicate the work can judge how the study was designed and conducted, and whether its results are reliable. ARRIVE was developed by the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) and is one of the reporting guidelines catalogued by the EQUATOR Network, alongside CONSORT for randomized trials, STROBE for observational studies, and PRISMA for systematic reviews.
ARRIVE 2.0 was published in 2020 (Percie du Sert et al., “The ARRIVE guidelines 2.0,” PLOS Biology), replacing the original 2010 ARRIVE checklist. It restructured the guidance into a 10-item Essential 10 — the minimum information needed to assess a paper’s reliability — and an 11-item Recommended Set that adds further methodological and contextual detail. Last verified 16 August 2026 against the official ARRIVE guidelines site (arriveguidelines.org).
The ARRIVE 2.0 checklist: all 21 items
The table below lists every item in the current ARRIVE 2.0 checklist, in order. Authors preparing a manuscript reporting in vivo animal research should work through the Essential 10 first — many journals require these at minimum — then complete as much of the Recommended Set as the study allows.
| # | Item | Set | What it covers |
|---|---|---|---|
| 1 | Study design | Essential 10 | The groups being compared, including controls, and the experimental unit (e.g., a single animal vs. a litter). |
| 2 | Sample size | Essential 10 | The number of experimental units per group, how the final sample size was arrived at, and the method used to determine it. |
| 3 | Inclusion and exclusion criteria | Essential 10 | Criteria set out before the study began, and how many animals or data points were excluded and why. |
| 4 | Randomisation | Essential 10 | Whether and how animals were allocated to groups randomly, and the method used to carry out and conceal the allocation. |
| 5 | Blinding/masking | Essential 10 | Whether those conducting the experiment, applying interventions, or assessing outcomes were unaware of group allocation. |
| 6 | Outcome measures | Essential 10 | The primary and secondary outcome measures, and, for any pre-registered study, whether they match the pre-registration. |
| 7 | Statistical methods | Essential 10 | The statistical methods used for each analysis, including any methods used to assess whether the data met the assumptions of the statistical approach. |
| 8 | Experimental animals | Essential 10 | Species, strain, sex, age, and other relevant characteristics of the animals used. |
| 9 | Experimental procedures | Essential 10 | For each procedure, what was done, how, when and where it was performed, and why the specific method was chosen. |
| 10 | Results | Essential 10 | For each experiment, a summary of results with a measure of precision (e.g., confidence interval), not just a p-value. |
| 11 | Abstract | Recommended Set | An accurate summary of study background, objectives, methods, main findings, and conclusions. |
| 12 | Background | Recommended Set | Scientific background and explanation of the study’s rationale. |
| 13 | Objectives | Recommended Set | The research question and, where applicable, any prespecified hypothesis being tested. |
| 14 | Ethical statement | Recommended Set | The name of the ethical review body or oversight committee (e.g., an IACUC) and the approval or licence reference. |
| 15 | Housing and husbandry | Recommended Set | Housing conditions, husbandry, and enrichment, reported to a level that allows another lab to replicate the environment. |
| 16 | Animal care and monitoring | Recommended Set | How animal welfare was monitored during the study, and any humane endpoints applied. |
| 17 | Interpretation/scientific implications | Recommended Set | Interpretation of results in light of study limitations, and their implications for the field. |
| 18 | Generalisability/translation | Recommended Set | Whether and how the findings are likely to generalise to other species, systems, or contexts, including humans where relevant. |
| 19 | Protocol registration | Recommended Set | Whether a pre-registered protocol exists, and where it can be accessed. |
| 20 | Data access | Recommended Set | Where the study’s data, materials, and analysis code can be accessed, or why they cannot be shared — see also a data availability statement. |
| 21 | Declaration of interests | Recommended Set | Any competing interests held by any author. |
Is ARRIVE 2.0 mandatory?
ARRIVE itself is not a law or regulation — it is a voluntary reporting checklist. Whether it is effectively mandatory depends on where a study is submitted:
- Journals: A large number of biomedical and life-science journals now require authors to submit a completed ARRIVE checklist alongside any manuscript reporting in vivo animal research, or explicitly endorse ARRIVE in their author guidelines. Check the specific journal’s instructions for authors, since the requirement (and which version) varies by publisher and title.
- Funders: Some funders and institutions reference ARRIVE as expected practice for reporting animal studies they support, separate from the ethical review and approval process itself.
- Ethical review vs. reporting: ARRIVE governs how a study is written up for publication. It is distinct from the approval process that authorises the study in the first place — in the US, oversight by an IACUC under the PHS Policy and the Animal Welfare Act. A study can be fully approved and still be reported in a way that fails the ARRIVE checklist.
How to use the ARRIVE checklist in a submission
- Work through the Essential 10 while drafting, not after the manuscript is finished — several items (sample size justification, randomisation method, blinding) describe design decisions that need to be documented as the study is planned, not reconstructed afterward.
- Complete the official checklist document from arriveguidelines.org, noting the page or section of the manuscript where each item is reported.
- Submit the completed checklist as a supplementary file if the target journal requests one, or attest compliance in the cover letter/methods section per that journal’s instructions for authors.
- Cross-check against the journal’s own policy — some journals still reference the original 2010 ARRIVE checklist rather than 2.0 in their author instructions, so confirm which version is expected before submitting.
ARRIVE vs. CONSORT vs. STROBE vs. PRISMA
ARRIVE is one of several study-type-specific reporting guidelines catalogued by the EQUATOR Network. They are often confused because they serve the same structural role — a checklist of what a paper must report — for different study types:
| Guideline | Applies to | Current version |
|---|---|---|
| ARRIVE | In vivo animal research | ARRIVE 2.0 (2020), 21 items |
| CONSORT | Randomized controlled trials in humans | CONSORT 2025, 30 items |
| STROBE | Observational studies in humans (cohort, case-control, cross-sectional) | 22 items |
| PRISMA | Systematic reviews and meta-analyses | PRISMA 2020 |
For a fuller map of which guideline applies to a given study design, see the EQUATOR Network guide. For the ethical and oversight side of animal research — the 3Rs, IACUC review, and the underlying law — rather than the reporting side, see Animal Research Ethics: The 3Rs, IACUC Oversight, and the Law.
Why ARRIVE compliance matters for reproducibility
Poor reporting of animal studies has been repeatedly linked to poor reproducibility in preclinical research — a paper that omits randomisation, blinding, or sample-size justification makes it impossible for readers to judge whether a result reflects a real biological effect or an artifact of study design. ARRIVE was built to close that specific gap. It sits alongside the broader set of reproducibility and transparency practices research administrators are increasingly expected to support, including registered reports, data availability statements, and structured reporting summaries such as the Nature Portfolio Reporting Summary. See CASRAI’s broader coverage of the reproducibility crisis and methods reproducibility for related context.
Frequently asked questions
What does ARRIVE stand for?
Animal Research: Reporting of In Vivo Experiments.
How many items are in the ARRIVE 2.0 checklist?
21 total: the Essential 10 plus an 11-item Recommended Set.
Who publishes and maintains the ARRIVE guidelines?
The NC3Rs (National Centre for the Replacement, Refinement and Reduction of Animals in Research), a UK scientific organisation. ARRIVE 2.0 was published in PLOS Biology in 2020.
Does ARRIVE replace IACUC approval?
No. ARRIVE is a reporting checklist for the published paper. IACUC review (in the US, under the PHS Policy and Animal Welfare Act) is the separate process that approves the study before it is carried out.
Is there an ARRIVE checklist for a specific journal I should use?
Check that journal’s instructions for authors first. Most journals that require ARRIVE point to the official checklist document at arriveguidelines.org rather than maintaining their own version, but some specify which version (2.0 vs. the original 2010 checklist) they expect.
This page reflects the ARRIVE 2.0 checklist as published by the NC3Rs and catalogued by the EQUATOR Network. Journal-specific submission requirements vary — always confirm current requirements directly with the target journal. Last verified 16 August 2026.
