PhD (at Oxford) vs staying at in the industry (Facebook) for a ML student? I am 26 years old and I got an offer for a PhD in Machine Learning at Oxford. However, currently I am a software engineer at Facebook and I am living a very well-off lifestyle. 

I applied for the PhD last year, not knowing if I would get it and I decided to work as a back up. Now that I have a great paying job it is hard for me to want to do the PhD even with the scholarship. However, I know the work I can get after completing a PhD at Oxford is much more interesting to me (my work is currently not very interesting) and I could be making more than I am now.

My question is: will it be worth it do take 3-4 years to do that PhD (and graduate around 30) or should I just stay at Facebook even though the job is not very interesting for me.
You must make this decision - no one else can make it for you. Things to think about:


Uninteresting jobs are bad. If you can't see your job getting more interesting, then say 5-10 years down the line there's a good chance you'll get so bored your performance starts suffering, and then you might get fired.
You know the industry very well since you have a first-hand insider view. What jobs do you enable by getting a PhD? If they're more interesting jobs (do you actually know they're more interesting, or do you just think they're more interesting?) that you will never be able to do without a PhD, that's a powerful reason to get a PhD. On the other hand, it's conceivable that you'll be able to do those jobs without a PhD simply by staying put, acquiring more experience, and doing well. You'll know better than anyone else. 
Do you have a significant other or a family to provide for? If so, what do they think? Remember that usually, once people experience a luxury, going back to a less-luxurious lifestyle is typically a big no-no even if it was previously acceptable. Even if you can accept it, your significant other / dependents might not.
What does your current manager or other senior colleague think (if you trust them enough to talk to them)? Just as important, are they willing to rehire you after you graduate?
Is it actually economically better to do a PhD? Run some calculations. If you stay put, you earn $X this year, $X + [increment] next year (if you have one), etc. If you go to Oxford, you earn $Y for 3 years where Y &lt; X, but then after 3 years you earn $Z where Z > X. How many years does it take before the second option exceeds the first, if it exceeds the first at all? The fewer years this takes, the more attractive the PhD becomes.


These things are too intricate to say more, unfortunately. As above, you must make the decision - no one else can make it for you.