Our research (me being one of the co-authors) consists of two main sub-cases which are too long to be in a single paper. So, they were divided into two parts--Part1 and Part2. Both of these papers contain the same text in many places (theory,introduction,procedure). The authors for both the papers are also the same.

If we were to submit this to two different journals, is it plagiarism?

  • 9
    If both papers are so similar, why not publish as one paper with 2 experiments? Doing so would allow you to shorten the entire document by reducing the intro and methods sections. If published as you describe, you would be committing self-plagiarism.
    – Inde
    Dec 30, 2016 at 16:36
  • 1
    Regardless whether it is plagiarism it's also bad style and as a reviewer I wouldn't stand for it.
    – user9482
    Jan 2, 2017 at 8:32
  • Don't do this, the self-plagiarism could cause retraction.
    – Nikey Mike
    Jan 2, 2017 at 17:05

8 Answers 8


If we were to submit this to two different journals, is it plagiarism?

Reusing text from another paper (even a closely related paper) without explicitly saying so would generally be considered self-plagiarism. Unless they have exceptionally permissive publishing agreements, you would be in violation of your agreements with both publishers if you didn't get explicit permission to do this. Even if the journals have the same publisher, they would probably still be unhappy, because this is a violation of scholarly norms.

If you feel your particular case is reasonable and would be considered acceptable in your field, then all you need to do is to be clear about it. Include a sentence like "For the convenience of the reader, Section 2.1 is copied verbatim from [citation to part 1]" and explain the situation to both publishers when you submit the papers. If they are OK with it (and you are honest with the reader), then everything's fine, but you certainly shouldn't submit the papers in this state without comment.

For this to work, you'll need permission from both publishers. In mathematics that would be an unusual request, and I doubt you would receive permission, but things may work differently in your field. In any case, you may come across as naive or eccentric if it doesn't work the way you expect, but at least nobody will be able to accuse you of being dishonest or manipulative.

  • @DavidSchwartz: Thanks, I removed the "yes" to clarify. I also added a paragraph to point out that the publishers may well not agree, but that's a different issue. Dec 31, 2016 at 16:42

Plagiarism is the use of others' ideas or distinctive language without sufficient attribution. Your question is about the amount of allowed duplication in your own work. That should (I think) not be talked about in terms of plagiarism. The term "self-plagiarism" is sometimes used for this, but I don't like it: the two academic crimes are inherently different because the victims are different. In a case of plagiarism, the primary plagiarized party is the victim. In a case of improper duplication, the victim is, in a more diffuse way, the rest of the authors' academic community: they are, in several different ways depending on the situation, "paying twice" for the same product.

So "Is this plagiarism?" is (I think) not the right question here. (Answer: not if each paper clearly cites the other and duplicated content is pointed out.) The right question is Is the decision to make two papers out of one project with a substantial amount of identical content serving the academic community well? What aspects of this course of action are potentially problematic, and what else could we do instead?

I would begin with

Our research (me being one of the co-authors) consists of two main sub-cases which are too long to be in a single paper.

How do you know your work is too long for a single paper? At least in my part of academia [mathematics], on the one hand the length of a single paper is quite variable: many papers are published each year which are under 5 pages and over 100 pages, for instance, and relatively few journals have strict length requirements. I have heard that length requirements are more common and more severe in other fields, but I would ask whether you are specifically violating the length requirements of all the best fit journals in your field. On the other hand, the length of an academic paper is quite fungible: in my experience, most papers can be compressed by up to 25% without a reader really noticing a change, and many papers can be compressed by up to 50% without ruining the core content. That amount of compression could solve your problem. Have you tried?

Sometimes people do have feelings that "this paper is too long," but that can be quite subjective. (For me as an author, fatigue starts to set in somewhere between 30 and 40 pages. After 40, the burden of keeping the entire paper in mind as any individual changes are made starts to feel significant. My longest paper is about 50 pages and had a very energetic coauthor.) If you are not actually violating length requirements or very clear norms of your field, I think it would be better to submit a paper which feels a bit on the lengthy side and see what feedback you get. Sometimes referees and editors recommend splitting a paper in two -- if you get such a recommendation, you can be more confident that you made the right decision.

Note also that your choice of "splitting" seems not to be a very natural one: you are not splitting the paper into two parts which can each stand on their own, and because of that you are repeating a lot. This makes me think that even if you have decided to write two papers and not one, a different way of splitting might make more sense. If your paper is unavoidably too lengthy to be published as one, then that should imply that you have enough academic content for two papers. What you have done so far -- repeating several sections verbatim for most papers -- is likely to create the impression among your readers that you do not have enough academic content for both papers but are trying to stretch one paper into two anyway.

Well, I hope this gives you some things to think about. I can't really give you the answer without seeing your paper. Among other things, it depends on the proportions of everything involved. If for instance the "theory, introduction, procedure" occupies two pages, and each case occupies 20 pages, then the amount of duplication is probably acceptable. Even in this case though a different reorganization might serve you better. In my experience, breaking something unnaturally in half and trying to publish each half separately can devalue your work: academia wants to publish "full things" rather than "half things". However, this is ultimately quite subjective, and with sufficient reorganization you could probably overcome this.

  • This really seems like it's more a problem of giving two people copyrights over largely the same work, so, yeah, plagiarism it is not. I agree that a better term would be useful.
    – The Nate
    Mar 10, 2019 at 18:24

In my experience, some repetition from authors in methods/procedures between publications is often permitted, even if it is technically self-plagiarized (though the original should still be cited, without question), because some techniques will simply be the same and there are only so many ways to say the same thing.

Duplication of an entire methods section is different, however, and should never happen because the work should never be exactly the same to be unique.

Having the same text in other sections, even just copying a few sentences, however, is quite bad form, and yes, I would say that is self-plagiarism. You have found a logical way to divide the results into two papers: there should be a logical shift in emphasis of the theory and background to match.

  • You seem to be assuming he won't disclose the duplication. Nothing in the question suggests this. Dec 31, 2016 at 10:43

The two subcases have in common the following:

theory, introduction and procedure

Pick one paper in which to explain these in detail. I'll call that one TBE (for Thorough Background Exposition).

Then in the other paper, give a brief sketch of the theory, introduction and procedure, and refer the reader to the TBE paper.

If it helps you -- you could think of the dividing up you're going to do as modularizing.


Why even worry about whether it's technically plagiarism or not?

Simply have the introduction and the preliminaries refer to their own use in another work.

It's easiest for the preliminaries, where you could either add this at the beginning:

In this section we present same fundamental definitions and basic tools necessary for our exploration of Foo. It should be noted that these are also relevant in the context of Bar, in a line of research which the authors { are currently pursuing | have pursued in [citation here] }.

or at the end:

The observant reader may note that the definitions and tools put forward in this section would also be relevant, as-is to the study of Bar etc. etc.

For the introduction the wording can probably not be generic, and I would weave in the mention of both Foo and Bar saying that this article focuses on Foo, while the authors are pursuing parallel work on Bar. Or something like that. As in the above, if something was already published, do cite it.

For both sections you don't need to spend more than 2-3 sentences to make sure you're self-plagiarism-free.


My way of dealing with this situation would be:

  1. in paper one: state that the problem will be solved in two parts and the second part is still in preparation and will be published as separate paper.
  2. in paper two: in the intro and method section write a statement that the paper is the continuation of paper one, then cite the first paper.

No, it would not be. The gist of plagiarism is that you misrepresent the authorship or originality of a work. So long as there is no misrepresentation whatsoever, there is no self-plagiarism and no plagiarism. So long as the later paper properly cites the former paper, there is no misrepresentation whatsoever.

Note that avoiding plagiarism by being honest about the duplication likely won't help you. You'll still have problems with getting the journals to accept the papers. The first journal will not be happy that you plan to publish a lot of the same content through another journal. The second journal will not be happy that much of the content has already been published in another journal.

  • 1
    For lengthy prose that is duplicated from another paper (even one by the same author), a blanket citation to the other paper isn't sufficient; it would need to be said explicitly that the duplicated prose is a direct quote from the earlier paper. Dec 31, 2016 at 3:07
  • @GregMartin Agreed. Honesty is essential to avoid plagiarism. Dec 31, 2016 at 4:13
  • I'd appreciate if the downvoters would explain their downvotes. The question was whether this is plagiarism with no suggestion that the duplication wouldn't be disclosed. If you are honest about the source, it's not plagiarism. Dec 31, 2016 at 10:43
  • Yes, if you cite correctly it's not plagitarism, but do you really suggest putting the whole introduction in there as a quote? No one does that, it looks pretty pathetic and the editor most likely wouldn't allow it. Also: the question is different and the way OP put it he cannot even cite the other paper since both will be submitted at the same time. So the question is about using the same introduction twice. And that's clearly self-plagitarism and not allowed.
    – user64845
    Dec 31, 2016 at 15:31
  • @DSVA No, it's not "clearly self-plagiarism". Plagiarism and self-plagiarism can only exist if there's misrepresentation and nothing in the question suggests that there will be any misrepresentation. I agree that it will look pathetic and editors will not allow it, but that doesn't make is plagiarism which requires dishonesty and/or misrepresentation. Dec 31, 2016 at 21:53

No. Plagiarism is defined as:

the practice of taking someone else's work or ideas and passing them off as one's own.

There are two essential elements both of which must be present: 1) it being someone elses work ... (it's not, it is the work of yourself and the co-author). 2) passing off ... again, you are not doing that either.

Plagiarism is in essence, breach of copyright, but in this case it is your work and you are free to re-use, re-pack and repeat as much and as often as you wish.

At worst, you are guilty of repetition.

  • Self-plagiarism is a valid and applicable concept. Discussing copyright is thoroughly inappropriate since this is very likely to be assigned to the publisher, and this is without getting to the ethics of reusing material which has already been credited.
    – Nij
    Jan 2, 2017 at 1:35
  • Plagiarism and breach of copyright have almost nothing to do with each other. You can commit plagiarism without breaching copyright, for example if you claim something is a work of original authorship that you didn't author when its copyright has expired. And you can breach copyright without committing plagiarism, for example if you correctly cite another's work but take almost all of it. Plagiarism and copyright are two completely different and almost entirely unrelated concepts and understanding that is absolutely vital to know whether or not you're committing plagiarism. Jan 2, 2017 at 5:02

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