A previous version of this question focused too much on my personal situation. The current one aims at being more generic.

The main question boils down to what are the advantages and disadvantages of having a broader PhD thesis?

In the context of a PhD student possibly working in a interdisciplinary field, what are the consequences of working on two (or more) projects, both related to the overall field but each project not directly related to each other? This is assuming there are no major concerns about graduating, the thesis committee accepting or being able to produce quality research.

More in particular, what are the (academic) career consequences of that? I would imagine it can make it easier to find a postdoc position, since the range topics you've worked with is larger, but how is it perceived?

I assume one of the major downsides is possibly the lack of focus. If it is still possible to achieve good research results in both areas (but clearly having fewer papers published in each subfield), are there other problems? Is it usually frowned upon?

  • 2
    This is a question for your advisor. Normally narrow, rather than broad, is the preferred option. But it ain't necessarily so. Early exploration is good, but the dissertation is very focused.
    – Buffy
    Sep 10, 2020 at 17:53
  • @Buffy thank you for your answer! I did talk with my advisors, but I got conflicting replies from the two of them. Or do you mean with advisor somebody else besides my supervisors?
    – Andrea
    Sep 10, 2020 at 18:06
  • 1
    No, the supervisors. Conflicting answers is a bad thing. BAD thing. Everyone needs to be on the same page. But if the one only meant keep your options open for a while, then it is probably fine. Your goal is to graduate, not to solve every open research problem in the multiverse.
    – Buffy
    Sep 10, 2020 at 18:08
  • @Buffy is graduating hard, if you've done good research for three years or so? Right now I am more concerned about my career options after my PhD, but I don't know if this is the right way to approach it
    – Andrea
    Sep 10, 2020 at 18:31
  • 2
    Your supervisors should be able to tell you about your progress. Most places, the dissertation is the proof.
    – Buffy
    Sep 10, 2020 at 18:34

1 Answer 1


There are dissertations of either kind: Those which are clearly focused on one topic, and those which cover a wide range of different topic under some rather loose "umbrella title".

Clearly, the traditional approach is the former. But the latter is rather common these days.

Whether the latter is acceptable depends on your committee, and thus to a large extent on the advisor who writes the report and sits on the committee. If that person/those persons agree, there should be no problem. Overall, as far as I can tell the latter should be no problem these days, as long as the overall scientific output is on par.

On the other hand, you should take into account that looking in too many directions at the same time might be detrimental to your PhD in a different way, if its consequence is that you explore many directions but complete none. In that sense, staying more focused is a "safer" option. On the other hand, a PhD is a good time to exlore different directions, if you make sure that you don't use this as an excuse not to get projects finished.

  • The OP can search this site for "stapled thesis" which gives some additional information. But that is only used in fields/institutions that permit (or even prefer) it.
    – Buffy
    Sep 10, 2020 at 18:11
  • 6
    @Buffy It is completely possible to do a non-stapled thesis (if I interpret the word correctly) with a wide range of topics, as well as a staped thesis with a coherent set of papers. I think this is a rather orthogonal direction.
    – user151413
    Sep 10, 2020 at 18:12
  • @user151413 thank you for your reply! Do you also have an insight on the consequences of choosing either option beyond my phd, with regard to career opportunities both inside and outside of academia?
    – Andrea
    Sep 10, 2020 at 18:42
  • 1
    @Buffy: I've seen several non-stapled theses that had two or more sections, each on different problems. One such is by someone who was a posdoc during my last two years of graduate school, working in the "Polish style" real analysis and topology group that my supervisor was in, and many others can be found by searching here with Thesis Keyword = topics (not all hits you get will be examples, however). Sep 10, 2020 at 18:56

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