Q: If the paper is published before submission of thesis then how to check for plagiarism?

It is an accepted practice to use your previously published papers in your thesis. In fact, many institutions encourage their students to present or publish thesis chapters prior to the submission or publication of the thesis. However, it is understandable that when running similarity checks with plagiarism detection software, a published paper would show high similarity or be flagged as plagiarism.

Let us first tell you what is really important in this case. It is imperative that you obtain permission from the journal where your paper was published. This can be done easily, and depending on the type of copyright agreement, the publisher should agree without a problem. You can then include a permission statement as a footnote or indicate that the chapter is slightly modified version of your paper reproduced with the permission of the copyright holder.

Note that self-plagiarism means the reuse of an author’s own previously written work or data in a new written product without letting the reader know that this material has appeared elsewhere. Not that text recycling per se is not the concern here; the “deception” or passing it off as a novel publication is. Thus, if you declare that the chapter has been published as a paper in a journal, it is not considered unethical. As for overriding the similarity check software, we recommend that you discuss this with your supervisor and analyze the similarity check reports carefully, omitting the paper from the plagiarism check of your thesis.

You may find this resource useful: [Series] Converting a thesis into a journal articl

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