Should you do a PhD?

by Linda Linsefors3 min read24th Jul 20206 comments

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Personal Blog
Career Choice

Note about my background: I did my PhD in Physics, in Grenoble, France. My impression is that the PhD system is quite similar for the rest of Europe and Canada. The US is significantly different, and I don’t know about the rest of the world.

Thanks to: Nandi Shoots, Gavin Leech, Daniel Filan and Callum Hinchcliffe for helpful comments and proofreading.


Sometimes someone asks me something along the lines of “Is it worth trading X years of my life to get a PhD diploma?”

My reaction to this is:

  1. If you put it like that, then obviously NO!
  2. You have no idea what a PhD is, do you?

A PhD is an entry level research job – nothing more, nothing less. Having a PhD is a requirement for some jobs, but so is X years of software development experience, or basically any other skilled job. There is nothing magical about a PhD, and like any other job (or anything really), if you’re just in it for the credentials, then there is almost certainly something better you can do.

You should not do a PhD just so you can do something else later. Only do a PhD if this is something you would like to do, in itself.

If you find yourself confused about the question “Should I do a PhD?”, just replace it with “Should I take an entry level research job?”


Now, if you are still considering doing a PhD, then there are some things you should know about that are particular to this career path. This is because there are ways in which academia is not quite like the rest of the world.

I’ve met many physicists who look back at their PhD as the time where they were most free to actually do research, before their time was taken over by teaching duties and bureaucracy. If you are only using it as a stepping stone to an academic career, you might miss out on the best part of this career path. I recommend that you try to do the research you really want right from the start – although this might be different in different fields.

You probably only get to do a PhD once. There is no rule about getting more than one PhD but some universities do not accept applicants who already have one, even in a different subject. I also think it is hard to get a second chance if you are a PhD dropout, but I have a lot of uncertainty around this. Because of this you should take extra care to choose your PhD position before you start.

As a general rule, you can take as much time as you want before starting your PhD without many consequences to your career (although I’ve been told that this is not true in maths, and there may be other exceptions too). But once you’ve stepped on the academic career path (getting a PhD is the first step), it is very hard to come back if you ever leave. It is also hard to change subject.

Think about how much you care about having an academic career after your PhD. If you do want an academic career you have to at least somewhat optimise for prestige. This means getting into the right institution, and publishing as much as you can in the right journals. Also find out how competitive it is to have an academic career in your particular field, and have some backup plans in case you can’t get a post-doc.


Probably the most important thing to keep in mind: make sure to find a supervisor that you get along with!

Professors become professors because of their research skills (or sometimes random luck, being in the right place at the right time, etc.), not for their people skills. Some PhD supervisors are great and supportive – I got along great with my supervisor – but I’ve heard stories of other PhD students who were not so lucky.

From what I have heard, these are some problems you might have:

  • Your supervisor never has time for you. This seems super common.
  • Your supervisor wants to be the first author on all of your papers even though you did most of the work, or your supervisor wants to be co-author even if they did nothing to help.
  • Your supervisor decides what projects you should do. This may not be a problem if you fully agree, or just don’t feel ready to choose your own research. But it is worth being aware that the amount of freedom you get can be very different depending both on your supervisor and on your funding situation.

You will probably talk to your potential supervisor when interviewing for a PhD position. Don’t be afraid of bringing up things that are important to you, like the amount of freedom you want, or making sure that you will get the support you need. If the professor is not supportive of you raising concerns, it is better to find that out before you take the job.

Multiple comentors on the draft of this post told me that it is an even better idea to talk to your potential supervisor’s current students. This seems like excellent advice.

At some PhD programs, you will not have a supervisor when you start out, but will pick one later after some initial studies. This gives you a bit more of an opportunity to get to know the potential supervisors before you commit to working with one of them. On the other hand, your pool of supervisors to choose from is going to be quite small, so you should make sure that there is at least one professor there who you would like to work with before joining the program.


This is definitely not the be-all and end-all of advice about doing a PhD. It is very different in different fields, institutions and countries, so make sure to find some specific advice for the area you are interested in.

If you are interested in doing a PhD in physics or AI Safety, feel free to contact me for more specific advice.

If you are still unsure, you can go through this checklist by Shahar Avin.

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