I am expected to finish my Ph.D. by the end of the year and I am seriously considering going for a second one. After finishing my master's in Biomedical Engineering, I became interested in Machine Learning and self-taught myself until I eventually landed a Ph.D. project in healthcare. At the risk of sounding cliché, the further I explored the field of ML, the more I felt my competencies were shaky at best. Now, this is not your typical "the more I know, the more I know I don't know" dilemma, since I have never had a formal background in the field.

Sadly, I now realize this Ph.D. was a terrible career choice, as was my choice of Biomedical Engineering for a minor/major.

Biomedical Engineering was a very fun but very challenging major. Fun in the sense that I had exposure to nearly all science fields. Challenging because I had first-contact courses at the level of other Engineering programs that had pre-requisite courses, forcing me to learn an insane amount of material in a semester, only to forget everything afterward since there was no follow-up. Thus, I feel like a true impostor, and sometimes I wonder if I should do another more focused major.

Regarding the Ph.D., I am in a peculiar position since I am pretty much the only one doing ML research in my group and the university does not offer graduate ML courses. Furthermore, since the funding comes from a European project with a specific goal, I have a very narrow set of tasks. I tried to learn everything I could myself, but since I never had a project where I could apply my new knowledge, I ended up needing to learn things over and over.

I would not say I was unsuccessful at all. I have published a technical paper in a top-tier ML conference and a clinical one in a top-tier medical journal (and have two of each kind just about ready to submit before I graduate). However, when I am looking for my next steps, I still feel like I barely know anything and that I will feel like an incompetent forever. I have a good relationship with my supervisor, but he has not published anything in the field for a very long time, so I am pretty much on my own all of the time. I like the freedom I have, but not having someone with field experience to discuss my ideas made me pursue a dead-end path for more than a year. Also, I am now struggling to incorporate the feedback I got when my last technical paper was rejected at a top-tier conference.

Thus, I would like some advice regarding my next move. I am confident I could take a few more practical data science courses to mitigate my blind spots (NLP, I am looking at you) and get hired for a standard Data Scientist job, but ideally, I would like to continue working in a science field. I am therefore wondering whether I should do another, proper Ph.D. since this one was a fraud. I am desperate to feel like I am knowledgeable about something for once in my life and that I am progressing towards a goal I am excited about.

Sorry for the long text. I appreciate your advice.

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    Your PhD is basically a piece of paper that you need to progress in your academic career. After a few years, nobody cares about what you did during your PhD. But everyone would question why you did a second PhD.
    – user9482
    Commented Jul 22, 2021 at 9:00
  • Right. I wonder if I will be able to transition to a new field like neuroscience as a PostDoc or industry employee with the current experience I have. Like, should I take a few months off to intensively work on new skills before applying to jobs or should I apply and try to get them on the job? Commented Jul 22, 2021 at 9:15
  • @astronat kind of. Although the general sentiment answers some of my concerns, I believe it does not directly apply because I feel like I got little value from this PhD Commented Jul 22, 2021 at 10:15
  • Doing a second PhD, unless you're radically changing fields, is telling the world (1) - you think your university made a mistake when they gave you the first one, and (2), by extension, you also don't think you can do research independently yet.
    – J...
    Commented Jul 22, 2021 at 16:19
  • @Roland More specifically, it's a piece of paper that's supposed to certify that you are able to learn independently and conduct research on your own within a broad area. So it might make sense to get a second PhD in comparative literature after getting one in the sciences, but it probably doesn't to get a second PhD in a related science field. Commented Jul 22, 2021 at 16:21

3 Answers 3


You are dramatically overestimating how much people will look into the details of your PhD. Nobody will read your thesis and, after you land your first job, nobody will care what it was about.

If you decide to switch fields, you'd be surprised how quickly people stop caring what your major was. You will are a STEM PhD first and foremost, and people will only care about details that are directly relevant to your/their work.

Two years of work experience in your desired career will quickly wash away whatever you think was "bad" about your PhD.

For what it's worth, your experience is not uncommon. Despite the (also common) imposter syndrome, you've developed independent research skills and established academic credibility. You're finally wrapping up and want to move onto something new after graduation (and, you guessed it, that's common too).

Finish your PhD and find a job you like in the field you want. That will help you much more than a second PhD.

  • 1
    While this may work in some cognate fields, trying to do this with "work experience" in completely unrelated fields (say, statistics and medieval French lit - and yes, I know of someone who did this) would be pretty hard.
    – kcrisman
    Commented Jul 22, 2021 at 13:24

Short answer: no

Longer answer: Finishing your PhD does not mean that you are done learning and improving. Everybody needs to continue doing that, and they do so without doing an additional PhD. Most (gradually) migrate to new topics, and learn about those through self-study or the occasional course/workshop. Most need to learn new skills; Many are shocked to find out when they got their first professorship that they are now more managers than researchers and need to learn a whole new set of skills. All universities I have been part of offered courses for early career researchers to facilitate that. The list continues. So it is normal that you are not "done" even though you finished your PhD. That unfinished state will hopefully continue for the rest of your life (your life would become pretty boring otherwise...).

  • Thanks for the advice! To clarify, I am not suggesting I want to be in a position where I am done learning. I love learning new things and my primary motivator is creating new things. The problem is that I feel my creativity is limited by my lack in background knowledge. I am about to graduate as a PhD in a field where first year PhDs probably know more than I do. Commented Jul 22, 2021 at 8:37
  • 2
    A PhD is not about getting background knowledge, it is vocational training for researchers. The emphasis is no longer on learning facts, it is about learning how to find those facts. So starting a new PhD because you want to learn facts is a really bad idea. Commented Jul 22, 2021 at 9:40
  • 2
    Maybe you can start a bookclub with fellow postdocs, and delve in some topics together with others. Some like to study on their own. Others like MOOCS. There are options to filling in background knowledge. Commented Jul 22, 2021 at 9:43
  • You are right regarding the PhD and learning facts. I am just worried that by not having the initial year of graduate courses a typical PhD offers, I did not get a "boost" in my background knowledge which would have been quite useful for my research. Thus, I am questioning whether I should re-do the process the "right" way. Maybe a second PhD is not the answer though. Maybe a postdoc is. Maybe a job while I do a second master is. This is the general advice I am looking for. Commented Jul 22, 2021 at 10:24
  • 1
    What you are feeling is normal, but is not a reason to continue formal education (i.e. getting a second master or PhD). You can, and should, fix relevant gaps in your knowledge, but you can do so without entering school again. Notice the word relevant: most of the things PhD students learn in their first year proof to be not important to them later on. Commented Jul 22, 2021 at 10:59

While I agree with the other responses, let me give you the perspective of someone who was part of a group where second PhDs were common. I think many of this will not apply in all countries (including the US), though.

Reasons to do a second PhD:

  1. Funding. Sometimes it is just about how someone can be hired. Also, in some countries PhD researchers are rather well paid so it can be an economic decision. (Also, in the country where this happened considers the PhD years as work experience, so years spent on the PhD are not "lost".)

  2. Changing fields. If the fields are too far apart, it could be a requirement to get a (faculty) job, publications in the field are not enough.

  3. Wanting formal supervision in a specialised field. As other answers and comments suggested this is not really necessary and a postdoc could work nicely to achieve this.

  4. Countries not recognising degree from certain institutions/countries. Sometimes degrees are not automatically recognised and naturalisation is complicated. This is less of an issue nowadays but it still could happen.

  5. Moving abroad.

  6. Practical reasons. For example, wanting to work with a particular advisor who needs to hire a PhD student.

+1 Fun.

This a compilation of reasons I have been told or have observed. Of course, this does not mean that doing a second PhD is advantageous from any other perspective. You will not necessarily get a better job or be more successful.

  • Even in the US, 2 and 3 can sometimes happen - I know of several examples, especially when the fields were separate enough.
    – kcrisman
    Commented Jul 22, 2021 at 13:20
  • 2
    And, honestly, it's pretty hard to completely switch fields without some minimal continuing income, and PhD programs may provide that ability to actually have the time to learn new field Y while not having to keep working 40-60 hours a week at X.
    – kcrisman
    Commented Jul 22, 2021 at 13:21
  • Thank you for the different perspective. I am in Europe so, for the most part, 1) applies (although I sometimes flirt with the idea of moving to the US because of the mind-blowing nature). 2 and 3 also apply so the question is whether I can get a postdoc in a different field having limited experience. Commented Jul 22, 2021 at 16:19
  • 1
    The difficulty in finding a postdoc in a different field is that you need to convince someone that they should choose you despite your different background. The positive part is that, if you find such a person, they tend to be open-minded and flexible.
    – Aolon
    Commented Jul 23, 2021 at 9:05

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