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I am planning to write several papers exploring various aspects of the same scientific question. Each of these papers must have an introduction which motivates it and explains the relationship between the problem and what others have studied in the past.

It would be fantastic if I could simply copy-and-paste the same introduction, or, at least, 90% of it. This seems to me to be ethically unproblematic. After all, I need to say the exact same things every time, and I certainly don't mind the self-plagiarism. Am I hurting the reader in any way? I suppose I might be, if the reader desired an introduction which consists of original material, but that is an odd desire, isn't it? Its the research, the stuff that follows the intro, that is original.

Sadly, I have gotten wind that the majority of the research community apparently does not agree with the sentiments expressed in the previous paragraph. This leads me here to ask a series of related questions:

  1. To what extent is self-plagiarism in non-technical bits considered acceptable? I often see authors recycle paragraphs but I have never seen anyone cut-and-paste the entire section outright.

    I'd be particularly interested in learning whether norms on this vary across different scientific communities.

  2. How often do scholars find themselves trying to same the same thing in different words to avoid self-plagiarism?

  3. Supposing I insert a sentence to the effect of: "The introductory section 1.2 is taken verbatim from the author's earlier paper [1]." How likely are journal editors and reviewers to complain about this?

By the way, I am fairly certain they would be very likely to complain about a sentence to the effect of "We refer the reader to [1] for motivation to study this problem and a discussion of its relation to prior work."

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Why not put all various aspects of the same question together into one paper? Can they fit? –  scaaahu Aug 19 '12 at 4:42
They sort-of fit, in that they are asking different questions about the same model. However, it would end up being a very, very long paper that, as a result, would likely go unread. More importantly, I am probably going to be thinking about these questions for years, so I'll have to face up to the dilemma in this question one way or another. –  alex Aug 19 '12 at 4:50
I've always wondered about this regarding my posters which all look the same. –  bobthejoe Aug 20 '12 at 9:00
I tend to agree with the comment about citing earlier uses. I'm curious what people think of the influence of "double-blind reviewing" where if you use a lot of earlier text and cite it you are also un-blinding yourself to the reviewers. –  Fred Douglis Dec 4 '12 at 23:31

7 Answers 7

Firstly, quoting any work, including your own, without explicit attribution of the quote, is going to earn you a very bad reputation for plagiarism sooner or later. Just say no.

Secondly, and to state the obvious, the introduction is there to introduce the rest of the paper. As each paper will be unique, so should the introduction be: the point is to lead the user into the paper, rather than to give a grounding in the whole subject area.

Thirdly, why not wrap up all of the things you want to say in all of the papers' introductions, into a single review paper? It would contain all of the literature review, motivations, unsolved problems, areas for future research, that you want to reference in your other papers. And then, those other papers can just briefly & concisely properly reference and quote the relevant bits of that review paper in their introduction. It won't be as brief as "for review and motivation, see my paper DOI:ABC.DEF.GHI", but you should be able to distil the review paper down to a paragraph or two for each subsequent paper, and those words will be unique for each subsequent paper, drawing only on the elements you need for that paper.

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I agree with this sentiment. While I don't think there's anything wrong with self-plagiarism per se, I have come across a set of papers written in this way, and as a reader it was pretty annoying to find the same text in each introduction. It meant I had to skip through stuff I'd already read to figure out what new stuff was being presented in the current paper. Having a unique and to-the-point introduction for each paper makes it easier for the reader to differentiate them. It should be done not for ethical reasons but because it's better writing. –  Nathaniel Aug 24 '12 at 17:53
I have seen papers whose introduction was (almost) a subsequence of the rest of the paper. Would the same apply here? I know it's annoying, but I don't see anything wrong. –  Raphael Sep 13 '12 at 8:14
I have to disagree with your first paragraph. Plagiarism means taking others ideas and/or words and passing them off as one's own. It follows that it is not possible to plagiarize oneself. Multiply publishing one's own ideas, words or work can be problematic, but I think it is confusing and unhelpful to call it plagiarism. Repeating yourself too much is inadvisable, but the repetition of one's own words and ideas is not inherently unethical or problematic. –  Pete L. Clark Dec 8 '12 at 18:33
Let me expand a little bit on the "problematic" part above: very occasionally in my field we discover that someone has published essentially the identical paper in two different journals. This is very bad: first, it causes a loss of esteem in the community. Second, every journal I am familiar with has a policy about not sending work to them which has also been sent elsewhere. If you do so, you are breaking a contract, so you may (and should, in my opinion) get in some real trouble. –  Pete L. Clark Dec 8 '12 at 18:38
But here the trouble is the specific broken contract. If I publish a paper and then later write a chapter in a book based on that paper, I'll be okay unless I've signed some insane contract with the paper's publisher. If I get suitable permission I can even include the paper in its entirety in a text. However, suppose I got permission from some publisher to include someone else's paper in my text and found that it was okay with them if I removed the author's name and replaced it with my own. I'm still committing the grave sin of plagiarism: no one party can excuse me of that. –  Pete L. Clark Dec 8 '12 at 18:45

Typically, you will not write all of these papers simultaneously in parallel, but one after another. And each time you write a new paper related to the topic, you will have a learned a lot more, and you will have a much better idea of how to explain the setting, what are the right definitions, etc.

Therefore you have a very good reason to re-write your introduction for each paper, and tailor it for the specific question studied in this particular paper. And this way there is no risk of anyone accusing you of self-plagiarism.

Incidentally, this way you can even go as far as experiment with different ways of explaining the basic setting of your work, and see if you get different feedback... After all, your introduction is the most important part of your work from the marketing perspective, and it is not easy to get it right.

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That is true. But it may be that even as your understanding of the technical parts evolves, your reasons for studying it do not. Moreover, you still need to cover your bases by saying "A similar question was studying 30 years ago in the paper [1]..." in the same way. So even while there is good reasons to rewrite a portion of your intro, copy-and-pasting a substantial portion of it would still be tempting (provided it were acceptable). –  alex Aug 19 '12 at 19:44

There is a very dangerous (for your career) issue here. If your papers are so similar that the same introduction could be repeated almost verbatim in each, it may be that the content of the individual papers don't represent a truly significant advance. As an obvious example, if you are just changing one parameter in your code and running it again, with no new analysis or insight, you will run into trouble and may even get banned from submitting to offended journals.

I realize this is not a direct answer to the question, but I think it may be useful to people interested in this question.

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I agree that this may be the case, but it isn't necessarily going to be the case. –  alex Aug 20 '12 at 18:50

As a referee, I would not have problems with either way of referencing your previous paper. I would be more pissed off if I checked one of your earlier papers and found that a section was ripped off that without notice.

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Even if the section had no technical content? –  alex Aug 19 '12 at 19:40
Yes, even if the section had no technical content. (But then I'd already be miffed that you included a section with no technical content; even a discussion of motivation and previous results needs some technical detail.) –  JeffE Aug 20 '12 at 2:03
@JeffE , you took my meaning too literally here; every section in a technical paper will have some technical content, of course. My meaning was that the section would not have any theorems, proofs, or technical arguments - just summaries of what other people have done as well as references to where, in practice, the problem under the question has come up. Apologies for stating my meaning imprecisely. –  alex Aug 20 '12 at 18:54

To what extent is self-plagiarism in non-technical bits considered acceptable? I often see authors recycle paragraphs but I have never seen anyone cut-and-paste the entire section outright.

There is no strict rule about that, apart from the fact that "the overlap between two papers must not be substantial". I think it's mostly a matter of content than size. For instance, if you were in your paper to reuse a technique/theory/tool that has been previously defined, by you or someone else. Then having a short section reintroducing the tool (for the sake of the self-containment of the paper) that is a copy/paste from another paper is OK. You found a nice and concise way to present a technique/theory/tool, there is no real need to reinvent it.

However, the introduction is quite different, because that's the part that motivates your paper, and present the results detailed in the paper. There is of course some high-level paragraphs/sentences that you can reuse (The need of general-appraoch is paramount in the context of general-problem because of general-reason), but somehow, if 90% of your introduction is the same than for another paper, then that probably means that either the 10% is not enough as a contribution alone (which doesn't seem to be the case) or that your introduction does not focus enough on why those 10% are important. If the major part of your 90% is background and related work, then move them to explicit sections.

I'd be particularly interested in learning whether norms on this vary across different scientific communities.

I couldn't speak for other communities, but something that is usually frowned upon (but many people still do it) in CS is "incremental research", where your next paper is just a small improvement of a previous paper of yours, and where your strategy from the beginning is to maximize the number of publications you can get from one idea, instead of trying to publish directly the full idea. In this context, self-plagiarism, especially in the introduction, could be seen as a blatant proof of incremental research.

How often do scholars find themselves trying to same the same thing in different words to avoid self-plagiarism?

Personally not that often, as I will mostly reuse "technical" parts, and try to write from scratch non-technical ones for each paper.

Supposing I insert a sentence to the effect of: "The introductory section 1.2 is taken verbatim from the author's earlier paper [1]." How likely are journal editors and reviewers to complain about this?

For the above reasons, I would complain about it: if your introduction is taken verbatim from another paper, then maybe the contribution of the paper I'm reviewing is not that novel. For background/related work section, I wouldn't bother mentioning that it's a copy/paste from another paper, however, I would certainly like to be directed to "full" version of the sections. Also, and that might be something field-specific, some submissions are double-blind, i.e., the reviewers are not supposed to know the identify of the authors, and obvious self-references are forbidden.

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You should definitely cite everything you copy verbatim, no matter what. (I.e., you should say something like "the following background information is repeated nearly verbatim from Section 2 of BLAH", so the situation is unambiguous. It's not enough to cite the source without making the copying clear.)

To see why, note that there are four possible types of people:

  1. People who think it is OK to copy your own text without citation, and think it is OK with citation.

  2. People who think it is not OK without citation, but is OK with citation.

  3. People who think it is not OK in either case.

  4. People who think it is OK without citation and in fact you must not cite it.

I don't believe people of type 4 exist. This means you should always cite any text you copy (even if you wrote it in the first place). There's no way you can lose: people of type 2 require the citation, people of type 1 don't mind, and people of type 3 are a moot point since they don't want you to copy it in the first place.

In practice, I think a large majority of academics are type 2, but it really doesn't matter.

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Recently, we submitted a paper to an IEEE Journal, the student in charge, apparently copied large parts of the text from a previous article we had in an IEEE conference.

We got a response letter from the editor that said something like this:

Every IEEE paper is checked for instances of plagiarism (including self-plagiarism), and we found that you made extensive use of copy-paste from your previous article BLA to write the current article BLA. I'm afraid I can't accept the paper with so much previously Published text.

Just a word of caution for these practices in IEEE Journals and Conferences

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In these days, checking copy-paste is easy. I am not surprised at all. –  scaaahu Jan 25 '13 at 9:21
Indeed, just wanted to help OP before he entertained the idea –  Leon palafox Jan 25 '13 at 9:28
"the student in charge" NO, that would be the authors. Signing on as an author means you take full responsibility for the work getting credit when it is deserved and taking blame when necessary. –  StrongBad Jan 28 '13 at 11:22

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