I am in the middle of writing my bachelor thesis and recently submitted a paper that I wrote with my supervisor about the same subject to a conference. If it makes any difference, I should mention that I am the first author. I would like to use the paper (15 pages) as the basis for my thesis (about 40 pages), i.e. I want to re-use most of its content without changing the wordings.

My supervisor told me that it is okay and I have read that it is even common practice among some institutions to reuse your own previous work for a bachelor, master or PhD thesis.

However, I am not quite sure if it is acceptable to reuse paragraphs which my supervisor wrote as co-author to that paper. In the Statutory Declaration that has to be attached to the thesis it is stated that I wrote the thesis just by myself with only the help of the cited material. Do I have to reformulate the ideas in this case?

2 Answers 2


Do you have a supervisor for the BA thesis? If so, that's the person to talk to. Assuming you get to choose a supervisor, it'd be sensible for you to pick the person you co-authored the paper with. Presumably, they will have no objection to using the text in full for your thesis (including the parts they wrote).

There's no issue with plagiarism, unless your institution has an unusual interpretation thereof. The point of rules against plagiarism isn't to make you pointlessly rewrite your previous work and in any case, co-authored papers don't allow for distinctions between the paragraphs you wrote or the ones someone else wrote, even if you personally can tell them apart.

It's also expected that a supervisor provided input to the thesis and (at least in the US) it's not unusual for that to include substantial editing or clarification. Especially if the thesis is good enough to be published down the road: might as well get started on the process early. You address this by thanking your supervisor in an acknowledgment section, along with other people who read your thesis or provided ideas.

Taking plagiarism rules literally would lead to absurdities like citing "personal communication" over coffee or drinks. If someone provides a really cool idea and you use it, it's polite to thank them in a footnote; but that's the extent of it. The point of the rules is for you not to go take an idea from someone else's paper, then claim it as your own insight.

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    "Personal communication" is exactly the right tool with which to cite a cool idea provided over coffee or drinks. One must always give explicit credit when using the words or ideas of another.
    – Bob Brown
    Commented Dec 24, 2015 at 15:44
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    Yes, my thesis supervisor is the person I co-authored the paper with. I will ask him explicitly. Good to have another view on this. Commented Dec 24, 2015 at 16:36
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    So I got in touch with my supervisor and he gave me full permission to use the whole paper within the thesis. That is why I accepted this answer. Commented Dec 24, 2015 at 19:07

You definitely can't present words someone else wrote as your own in your thesis.

While it is common to reuse prior work in theses (as long as that work wasn't submitted for credit previously), things are obviously complicated when that prior work has co-authors. I don't have experience to say what would be acceptable, but I would be very cautious. To stay safe I'd advise not incorporating any of that work directly, but instead citing it as you would any other source. But that probably means you won't get fifteen pages out of it...

  • Thanks for your advise. I need to use parts of the paper because it covers the core subject of the thesis. It was intended by and discussed with my supervisor that I would submit the paper about the same subject and then extend it to a thesis. As I know which paragraphs I wrote, I assumed it would suffice if I just rewrite everything that he touched. Commented Dec 24, 2015 at 13:17
  • Plagiarism extends to the source of the ideas not just their wording, so that may or may not suffice. Your university would have a legal department; it may be worth getting them to look at the details of your situation. Commented Dec 24, 2015 at 13:20
  • @curiousdannii Plagiarism is not a legal offense like copyright - it is an academic honesty issue. A lawyer is not the right person to ask. Commented Aug 1, 2022 at 19:13

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