Guaranteed advisor in choosing a PhD program

Question

I am currently in the process of deciding between two PhD programs. One program is at a university with a very new thrust in the subfield, while the other is at a university known for having a more established program in the subfield. I'm seeking advice on a couple of points of uncertainty.

The first university only has one faculty member working in theory for my subfield of interest. However, he has agreed to supervise my PhD. His specific research seems interesting and he is very well established and productive in the field, but is not what I'm currently most excited about.

The second university boasts a more established program (overall and in the subfield) with a better ecosystem (student strength, collaborations with other institutions, etc.), including several faculty members whose research interests are very exciting to me. However, these faculty members have all indicated that they cannot take any new students this coming fall either due to funding or too many current students, though there might be an opportunity in the following year(s). This situation presents a potential risk of not having a committed advisor immediately, which seems to be a common scenario for entering theory students at this institution. At worst, I might not find any advisor in the subfield within the first year to two years and would have to switch to a different subfield for my PhD.

Here are my questions:

Considering my undergraduate GPA was on the lower side compared to typical admits, is it likely that the hesitation from faculty at the second university to commit to taking new students immediately is influenced by their assessment of my academic record? If this is the case, it seems there would be a chance to make a better impression through strong performance in the first year.

Is it generally more advisable to choose a program where a guaranteed advisor is in place from the start? From speaking with theory students across programs in my field it seems that taking on the risk is quite common, but I have the option to avoid that situation entirely.

Answer 1

In the US, if you can secure a TA for funding, or a general RA, then you probably can do fine at the place that won't make any guarantees on entry. Such a guarantee is a bit unusual in most places in the US in any case, especially if comprehensive exams are part of the process.

I doubt that either option is poor, actually.

But, in either case, you may need to compromise somewhat in the doctoral research to find a suitable advisor. Don't insist too much on specifics. You are at the start of a career, of course, and can change direction once established. Don't let the perfect be the enemy of the good.