Switching Phd topic (and advisor)

Question

I am a PhD student in computer science. My current advisor was also my masters advisor, and I stayed with him for a PhD because back at the time the research I did under him was interesting for me. Two years into the PhD, after talking with friends from grad school and exploring different fields in CS, I found myself increasingly drawn into a different topic. I waited for a while, just to make sure this is not a "whim", but a real change in my interests. At this point I am absolutely sure that new field is what I want to do (and also in terms of after the PhD).

My current advisor cannot advise me in this new field, since this is not his field. I talked to the dean of my department, and he said that in this case it makes sense to find a new advisor, and just move. I am ok with starting over after two years, but I really feel bad leaving my advisor, after they spent so much time and effort in me. They funded me for the whole time, helped me navigate through the university bureaucracy, helped me to get scholarships (the last one is a pretty big one which I just received, and it made me feel so bad to accept it and leave. Needless to say, when I applied for it I did not know that leaving my advisor would be the option suggested by the dean).

I do not have one sharp question, but I need advice: how common is it? Should I offer to return the scholarships? How should I present it to my current advisor? (they don't know about me planning to leave, but it won't be a surprise for them at this point)

Answer 1

Switching advisors is common, but not extremely common. There are hundreds of reasons for it, but wanting to do a different topic is likely one of the rarer ones, especially if it results in lost time to completion. Even changing universities to find a better/more compatible advisor happens often enough. There are some bad advisors out there, but it isn't an extremely common occurrence.

If your time to completion is reasonably short, I'd suggest you just continue in the short term. You seem to have a really good advisor, which is a big plus and not guaranteed if you switch.

If the new track is somewhat similar to the current one, especially in research process, then you can certainly take it up in the future when you have a secure position. You aren't locked in to the topic of your dissertation through your whole career. The question is when is the best time to make a change. Usually that means early, if possible, but not if it delays your career. Think long term.

But for the case where the new field is very different, then staying where you are may just be wasting time. But think about the research process in the two fields. In mathematics and in history they are very different. In mathematics and CS they can be similar or quite different. The doctorate will give you skills in process, not just in topic.

But the bottom line advice is to consider your own needs and career, not the feelings of your current advisor. It is you that will live with the decision and most advisors will understand that you and they might have different goals.