Answering the "why do you want to do a PhD?" question This question is ubiquitous when applying for PhD studies, and it's one I don't understand. On the surface it's a simple question, but I found it to be frustratingly complex.

I tend to think in economic terms. My calculations indicated that PhD studies are not worth it, especially in a world of exponential growth. The details aren't that important, but briefly, I calculated that if I stay in industry and invest most of my salary into the stock market, I can expect to greatly outperform someone who spends 4+ years in a PhD program unless he or she commands a very high starting salary, which is usually not the case. This doesn't take into account the fact that 49% of PhD students are depressed
 and half of them don't complete.

So since the economic argument is a failure, when I wrote my PhD applications, I put in all the other reasons I had to do it, such as:


I felt I'm in a dead-end job where my skills aren't appreciated. A much less-trained person can do what I'm doing, and while I believe I do a better job, I do so in ways that management does not track.
I wanted to swap careers. To do that I needed a new set of skills, and further study would not only let me pick that up, it would let me back up my skills with a paper qualification. Since I already had a Masters degree a PhD is the next obvious thing to do.
I choose this field because it provides transferable skills to the careers I want to move to, and because I'm sufficiently interested in it to want to keep up to date with its most recent developments (even though I probably won't stay in it as a researcher, per the fact that the odds of finding an academic job are very low).
I did well in my Masters (which was in the same field), including the research component, so I believe I can also do well in a PhD.
I can afford it. I hadn't been in the workforce for long, but I'm extremely conservative with money and we've been in a bull market for the past several years. Of course I would rather not self-fund, but if I have to, I can.


When I showed these reasons to my professors, they responded with "you are telling them why they shouldn't admit you!" Following their advice I rewrote my statement of purpose to what I'll call half-truths, which got me admitted.

I don't understand why my original reasons to do PhD studies weren't valid. I'm happy doing what I'm doing right now, and my supervisor has said I'm progressing well. That seems to be indicating that my original reasons aren't inappropriate. I further don't understand why PhD programs care about the reasons why the student is doing a PhD. It seems much more natural to worry about whether the student is capable of doing it. Certainly the latter question was the focus of all my non-academic job interviews. Finally it seems admission committees like candidates who are passionate about the field and want to become researchers themselves. However I also see plenty of complaints by academics about academic life (e.g. the funding lottery, the nomadic lifestyle). If academics are trying to convince students that they shouldn't try to be researchers, why are they turning around and looking for people who want to be researchers? It feels like they prefer the ignorant and starry-eyed over those who're aware what they're going into.

Can someone explain?
Let's consider why &quot;you are telling [professors that] they shouldn't admit you!&quot;:


I felt I'm in a dead-end job...


That doesn't show motivation for doing a PhD.


I wanted to swap careers...


You don't need a PhD to swap careers.


I choose this field because...

...it provides transferable skills to the careers I want to move to...

This requires more detail to be relevant.

...because I'm sufficiently interested in it to want to keep up to date with its most recent developments...

You can do that without a PhD

...(even though I probably won't stay in it as a researcher, per the
fact that the odds of finding an academic job are very low).

This doesn't show motivation for doing a PhD.


I did well in my Masters (which was in the same field)...


Many &quot;do well&quot; in their Masters, PhD students do better.

...including the research component, so I believe I can also do well in a PhD.

This requires more detail to be relevant.


I can afford it.


This doesn't distinguish you.