Self-Plagiarism: Can You Reuse Your Own Work?

cutting up lines of paper with text with scissors
Copy-pasting your own academic work into a new study without attribution can land you in hot water.

The Internet has made it incredibly easy to find and copy-paste any kind of content, including academic work. And with universities and publishers gearing up for the fight against plagiarism, most students and researchers are well aware that passing someone else’s work off as their own is not only unethical–it can have severe consequences for their academic career. 

What researchers might NOT know is that, even if you only use your own ideas, research, and words, you might actually plagiarize yourself. You might be asking, “How can I plagiarize myself?” Well, misleading your readers (either intentionally or accidentally) by presenting your previous work as new work is called “self-plagiarism” and is usually treated just as seriously as other forms of plagiarism.

What is self-plagiarism exactly?

Self-plagiarism means reusing any kind of work that you have already submitted or published without citing this work. This content could be data, an entire paper, parts of a paper, or graphs from an old paper. Essentially, if you are making the reader believe that this work is new and original when it isn’t, then you are plagiarizing. 

The American Psychological Association calls self-plagiarism “unethical”, deceit, and a potential copyright violation. But since not all cases of text or data recycling are ethically or legally problematic, even publishers and researchers do not always agree on what and how much reuse of one’s own published work is acceptable. BioMed Central, in collaboration with the Committee on Publication Ethics (COPE), has therefore recently developed a set of new guidelines to help editors handle cases of text recycling, which are continuously updated in line with new developments.  Whether you are a graduate student or are submitting your own research for publication, this article contains all you need to know to make sure you avoid plagiarism–even of your own work.  

Table of Contents:

  1. Obvious cases of self-plagiarism
  2. Less obvious cases of self-plagiarism 
  3. Why is self-plagiarism problematic? 
  4. When is recycling work acceptable?
  5. How do you avoid plagiarizing yourself?

Obvious Cases of Self-plagiarism 

The following are more clear-cut cases of plagiarism. You should by no means engage in the following for any academic work: 

  • Handing in an essay or assignment you have written and already used for another course
  • Reusing data, results, or text passages from your (unpublished) or bachelor’s thesis for your master’s thesis without acknowledging where this material comes from
  • Submitting a manuscript to a scientific journal that contains data, text, or conclusions that were already published in another journal, in a book, or at a conference without informing the editor/reader

Less Obvious Cases of Self-plagiarism 

In other cases, using your own work without attribution can land you in a grey area. Consider the following cases and always err on the side of caution when it comes to using, citing, and referencing another author’s work

  • Copying (parts of) the method section or images from one of your earlier publications into your current manuscript due to same methodology and design: You might think that you are the intellectual owner of your work, but what usually happens when your paper is accepted by a journal is that you hand over the copyright to the publisher. The publication therefore becomes the property of the journal and even you, the author, are not allowed to reuse any of the published material without correct citation and/or permission. Open access journals that use Creative Commons licenses usually allow you to reuse your work. But you still need to cite your original publication and make sure you do not pass off parts of old work as new material.
  • Splitting one large study into a number of smaller ones to get more publications out of it: This approach is called “salami slicing.” While it might help you grow your publication list, it also potentially distorts the scientific output and can harm your reputation in the long run. Many journals now try to prevent or at least detect such practices by asking authors to list their recently published or submitted work on the same topic before making a decision on sending a manuscript out for peer review.
  • Translating earlier work from another language and passing the translated version off as original work: This type of plagiarism might be more difficult to detect, but it comes with the same problems – misleading your readers, copyright infringements, and potential harm to your reputation if someone does make the connection between the original and the translation.

In a Nutshell: Why is Self-plagiarism Problematic?

Here are the major reasons why self-plagiarism could be a problem for any author who chooses to reuse their own work:

  • University plagiarism policies vary, but resubmitting is always a violation of academic integrity and considered misconduct that can result in a failing grade on an assignment. A repeat offense could also lead to more severe consequences such as suspension or even expulsion. 
  • While not every academic or publisher agrees that self-plagiarism constitutes a real case of academic misconduct, it is generally considered a violation of scientific integrity and can undermine not only your own reputation but also the public’s trust in the scientific process more broadly.
  • As mentioned above, if your work appeared in a scientific journal or in a book, then you most likely handed over the copyright to your publisher. By reusing it without permission and/or clear citations you are violating copyright laws.
  • Since most journals now use plagiarism detection software at submission to prevent duplicate publications, your copied text will usually be flagged. Even if your manuscript is not outright rejected at this stage, you will be asked to rewrite and resubmit it, which will ultimately delay the publication process. Since many cases of self-plagiarism happen because authors who feel the “publish or perish” pressure that can be especially strong at research universities are trying to save time while getting as many publications out as possible, submitting plagiarized work can easily backfire.  

When is it Okay to Recycle Your Own Work? 

Reusing your own work is only acceptable when (1) it is necessary to do so for your paper; and/or (2) you have clearly indicated or cited your previous work in the text. You may translate an article that was published in your mother language into English to make it available to the international research community. But you may not pretend that it has not been published before. 

That means, for example, that you cannot count both versions as separate papers on your publication list. You also might need to use published material when you write a book or contribute a chapter to a book on a topic you have been working on for some time. Again, this is not problematic if you cite all sources correctly and inform the editor/publisher about what parts are new and original and what parts are taken from your earlier (maybe even unpublished) work. Make sure you also talk to everybody else who was involved in any of the work you intend to reuse and get their permission in advance.

How to Avoid Plagiarizing Yourself

Here are some fairly easy guidelines to follow to ensure that you don’t accidentally plagiarize your own work.

  • Do not reuse assignments or any kinds of student papers without talking to your professor/supervisor first.
  • Cite your already published work when necessary (e.g., “we used the same method described in Smith et al., 2020”) rather than directly copying text from an older publication into a new manuscript. Alternatively, you can paraphrase your text as much as possible, but still refer to your earlier publication. Knowing how to paraphrase in academic work is an invaluable skill for all researchers. Journals often accept more duplicate text in the method section that in other parts of an article, but you can avoid delays caused by some back-and-forth between you and the editor if you make sure that the amount of duplicate text is well below the amount of new text and does not “overshadow” it.
  • Do not try to pass off old ideas or concepts as new. If you have already published several articles on a subject or a method you developed (maybe in a different language), then do not present your approach as something you just came up with to make it sound more interesting or relevant.  
  • Understand the guidelines of the journal you are submitting to, and only provide the required plagiarism statement(s) (e.g., “the work presented here has not been published before”) if they are true and applicable for your document. When in doubt, contact the editor before submission or address potential issues in the submission cover letter.
  • Do not send the same manuscript to several journals at the same time, nor a translated older article to a new journal, unless the target journal guidelines specifically allow you to. You can only submit a manuscript to a different publisher after it has been rejected or after you have officially withdrawn it. 
  • Contact everyone listed as an author on the earlier publication if you do have to reuse already published work, and get their permission before taking any action.