Self-plagiarism is the reuse of your own previously published words, data or ideas in a new work without disclosure or citation, in a way that misrepresents the new material as original. It spans a spectrum from minor text recycling — reusing passages of one’s own writing — to duplicate publication, the most serious form, where substantially the same study is published more than once.
The issue is not that reusing your own work is forbidden. Researchers legitimately build on their prior contributions. The problem arises when reuse is undisclosed, so readers, editors and the literature are misled about what is new.
A spectrum, not a single offence
These overlapping terms describe behaviours of differing severity, and treating them as one blurs an important distinction.
| Term | What it describes | Typical severity |
|---|---|---|
| Text recycling | Reusing one’s own previously published text (e.g. methods passages) | Context-dependent; sometimes acceptable |
| Redundant / salami publication | Slicing one study into multiple thin papers | Inflates output; misconduct if undisclosed |
| Duplicate publication | Publishing substantially the same work twice | Serious misconduct |
Because severity varies, editors assess each case on its facts rather than applying a blanket rule — an approach reflected in research integrity practice generally.
Why undisclosed reuse is a problem
Duplicate and redundant publication distort the record in concrete ways. They can over-count a single piece of evidence — a particular risk in systematic reviews and meta-analyses, where the same dataset counted twice silently inflates apparent support for a finding. They can also misrepresent productivity and waste reviewers’ and readers’ time. Undisclosed reuse therefore undermines the verifiability and credit functions that citation exists to protect, which is why it sits within the family of plagiarism-related concerns.
COPE guidance and the role of disclosure
The Committee on Publication Ethics (COPE) provides guidance that editors widely follow on text recycling, redundant publication and overlapping submissions. The consistent theme of that guidance is transparency: reuse that is disclosed, cited and permitted is handled very differently from reuse that is concealed. COPE has developed dedicated guidance on text recycling that distinguishes recycling in different parts of a manuscript and at different stages of publication, recognising that some recycling — particularly in methods — can be legitimate when acknowledged.
The practical implication is that disclosure converts a potential problem into a manageable, ethical practice. Concealment is what turns reuse into misconduct.
Acceptable reuse versus misconduct
The line is drawn by disclosure, permission and proportion, not by the mere fact of overlap.
- Often acceptable: reusing standardised methods descriptions where wording is necessarily similar, provided the source is cited; building a new analysis on previously published data with a clear citation; reusing material in a thesis later developed into articles, where disclosed.
- Generally misconduct: publishing the same findings in two journals without telling either editor; presenting recycled text as new without citation; splitting one study into several papers to inflate a publication count.
Copyright adds a further dimension: even your own published text may be owned by a publisher, so reusing it can require permission as well as citation.
How to disclose and cite your own prior work
Handling reuse correctly is straightforward when approached deliberately:
- Cite yourself. Treat your earlier publications exactly as you would another author’s — with a full in-text citation and reference entry.
- Disclose to the editor. Tell the editor at submission about any overlapping or related work, including manuscripts under review elsewhere, and supply copies if asked.
- Use an unambiguous identifier. Link your works through an ORCID iD so your own output is reliably attributed to you and easy to trace.
- Quote and mark recycled passages. Where you reuse your own wording, signal it and cite the original rather than presenting it as new.
- Check permissions. Confirm whether copyright permits reuse of the specific material.
These habits sit alongside good authorship practice and the general guidance in our resources for authors.
Frequently asked questions
Is self-plagiarism really plagiarism?
It is a related form of research-integrity concern. The mechanism differs from copying another author — you are reusing your own work — but the harm is similar: undisclosed reuse misleads readers about what is original. Disclosure and citation are what keep reuse legitimate.
Can I reuse my own methods section?
Often yes, when the wording is necessarily similar and you cite the original publication. COPE’s text-recycling guidance recognises that some recycling, particularly in methods, can be acceptable when disclosed. Reusing results or conclusions as if new is a different matter and generally not acceptable.
What is the difference between redundant and duplicate publication?
Redundant (or salami) publication slices one study into several overlapping papers, while duplicate publication republishes substantially the same work. Both distort the record when undisclosed; duplicate publication is generally treated as the more serious breach.
How should I disclose overlap with my earlier work?
Cite your prior publications in the manuscript, inform the editor of any related or overlapping work at submission, and provide copies if requested. Consult the CASRAI dictionary for standardised definitions of these terms.
