Q: Is submitting a thesis chapter to a journal considered duplicate submission?
Is it regarded as a duplicate submission if I submit the part of my doctoral thesis (one chapter) to a journal? I changed the language, and did some paraphrasing and deletion.
It is an acceptable practice to convert an entire thesis or parts of it into one or more articles and publish in a journal. Most journals will not have any issues with this as long as you declare this in your cover letter and of course, cite the source in your manuscript. Moreover, since you have paraphrased and made relevant changes to the chapter, I don't think you will have any problems at all.
One point to note, however, is that a thesis chapter and a journal article are two completely different sub-genres of academic writing. Each caters to a different audience and sets different expectations. Therefore, take care to ensure that your manuscript uses the style, structure, and format of a journal submission.
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This content belongs to the Conducting Research Stage