Including part of master's thesis in one's dissertation

Question

I just want to make sure that I understand this issue correctly. My situation is that I developed a chapter of my master's thesis as a chapter in my PhD dissertation. It is a substantial revision but they do have some overlaps.

I did some research online about self-plagiarism. Here is something I find that is confusing:

(1) Many people say that if my dissertation includes part(s) of my master's thesis, I need to cite them correctly otherwise it would be self-plagiarism.

(2) I also see many people publish chapters of their phd or master's thesis as single articles directly without being criticized as self-plagiarism.

To me, this obviously shows that the reason why most people take case (1) to be self-plagiarism is not about copyright of the master's thesis. If it were about it, then the case (2) should have been self-plagiarism too.

The most reasonable conclusion for me seems that case (1) is not self-plagiarism, but something to avoid nevertheless. Because one wants the PhD dissertation to be something new and something representing one's doctoral research. But if so, I see no reason not to include a substantially revised chapter in my master's thesis in the dissertation, because the substantial revision represents my doctoral research (and my committee agrees).

Am I right? Is there anything I missed here? Thank you.

Answer 1

As others have said, it really does depend on the policies at your institution and where you earned the master's vs where you are completing the PhD. My understanding is that we're typically allowed to include revised versions of our theses and relevant graduate course work from the PhD granting institution in the dissertation. You wouldn't need to cite it unless it has been published (see below). These can be thought of as early drafts of ideas that eventually made it into a dissertation chapter. If you earned the degree elsewhere, there's a pretty good chance it made it into a searchable database, so you can't copy and paste. If you are substantially revising the thesis and turning it into a single chapter, then I would add a foot note that says an earlier version of the chapter was submitted as a master's thesis and cite it. Same if the dissertation is a series of published articles. Just note where they were published, cite, and move on. You probably don't need to cite individual page numbers unless you want to do some commentary on where the content has changed substantially.

I should note that, if you are very early on in your PhD, there's a pretty good chance the submitted dissertation will have none of your master's work. I have 2 masters with 2 theses, and I originally intended to include substantial parts of include both in the dissertation. By the end, the writing style and the ideas were so under developed compared to my more recent work that they had to be dropped.

Answer 2

The best answer to your question in your specific case is to check the guidelines for PhD examinations. In these rules, it is established what will be considered relevant for passing the PhD exam, which includes submitting a thesis. Every respectable university has these rules.

If you cite parts of your Masters thesis, clearly state where you do so.

Some universities allow cumulative theses, so plagiarism is explicitly 'allowed' for them. Some only allow a monograph, where plagiarism is explicitly forbitten, i.e. direct copy pasting. In the latter case, you are still (often) allowed to use your published results, if you rewrite everything and present it in a flow in the monograph.

Answer 3

In most systems, you can't submit the same work for two different degrees/exams. You should cite your MA thesis and develop new research that builds upon it and goes beyond it.

You'll have to check with your home institution for the exact rules that apply to you but you need to be doing NEW research for your PhD.