Usefulness of research paper(s) of another discipline for PhD

Question

Consider the scenario in which a PhD student of the subject X published good research papers on subject Y. X and Y are not related. Will those papers any way useful for getting PhD or any benefits related to PhD?

Answer 1

It is unlikely that any papers in a different field will be used in assessing a PhD. However, as long as the papers are not too time consuming to generate, then the process (doing research, writing it up for publication, responding to reviews) will be useful for doing the work necessary to get your PhD. And more papers will always help in applying for postdocs.

Depending on the subject, a PhD can be more about learning to do research than obtaining subject matter knowledge. If you are in such a discipline, then research practice is useful. But it is counterproductive if doing the extra papers reduces your capacity to do research in your own field (particularly time).

Answer 2

I don't believe there can be a general answer to this other than it depends. Depends on university, on country, on field, etc. Generally, though, I would guess that in most cases the value would be pretty small unless the research methodologies in the two fields are similar.

If you want to pursue a doctorate in Mathematics, anyone considering you will want to know that you have the basis and background for research in mathematics. Having published in Chemistry isn't going to have much value since there is little either in the background or the methodology that will help you in maths. Medicine and Chemistry would be a different story, perhaps.

But if you have the required background in discipline, then such other work could have a small effect as it gives some evidence of deep thinking and hard work.

Such disparate interests can also raise questions about your commitment to the new field, of course. I doubt that would be disqualifying, but you should be prepared to discuss the issue.