Do US PhD programs prefer applicants without a Master's degree?

Question

The question is essentially in the title. Do PhD programs in the United States prefer it if an applicant does not have a master's degree beforehand? This question is particular to engineering, as I think the answer varies even within STEM.

As far as I am aware, most US PhD programs will accept applicants with a bachelor's degree, and these candidates can earn a master's degree along the way, or if they drop out. I get a slight feeling that programs prefer such applicants, but if so, I can't think of any reason why. Is it because they are a little more raw, and the program can shape the path of such students to a larger extent? (That doesn't sound convincing to me, at all.)

With a master's degree, the applicant already has some experience of graduate school, and possibly even research. Are there any reasons this would work against them?

Answer 1

Given that the design of US doctoral programs is to enable those with a bachelors to succeed, the answer would be, structurally, yes. But for the admission process itself, the effect, while variable, I expect to be weak - with caveats.

There is, in the US, normally some sort of qualifying process before one formally begins dissertation research. Some places and in most (other) fields this takes the form of qualifying examinations; written and/or oral. There are other processes possible, however, probably more likely in engineering.

But there is likely to be some process and the early part of the doctoral curriculum (coursework, lab experience,...) is designed to make passing the bar possible. Usually the early work also guarantees broad knowledge of the field in general before deep specialization for the dissertation. This will also benefit future academics and prepare them for a career. Note that the faculty is pretty certain of the general knowledge of a student who goes through this long process successfully.

For a person with a masters in hand, the qualifying process is probably still in place. I'd expect that having it waived would be rare. This makes it more difficult both for the applicant and for the faculty to judge whether they have the general knowledge or not.

So, a "preference" is probably too strong. But "extra scrutiny" may well be in the minds of the committee members if that is the process for successful admittance.

On the other hand, if a professor has the authority to accept individuals on their own (and probably to give them financial support), the balance may change in the opposite direction. If a professor has need of someone with particular skills in their lab, then someone with a masters might be preferred, being farther along in their education. But the qualifying bar may still be in place, giving the candidate extra tasks, perhaps.

My recommendation is that if you are already in a masters program, then finish it. But if you are not, then there is little if any advantage in starting one if your goal is a doctorate in the US.

Answer 2

This answer is really about some (and not all) top programs in mathematics, but perhaps it applies more widely.

A number of top PhD programs see their main mission as training future top mathematicians, maybe not just Fields Medalists, but folks at the level of invited speakers at American Mathematical Society meetings (of which there are around 40 a year). (Note that, with the current scarcity of jobs, we are near the point where most people hired into tenure-track positions with significant research responsibilities have demonstrated potential to do research at this level. I don't think it is unreasonable for a top 10 department to think of their graduate programs this way.)

Certainly there is some extent to which mathematical potential is inborn, or at least determined before graduate school. (We don't argue that people with moderate or severe intellectual disabilities can do mathematics research.) Some minority of mathematicians, large enough to be influential in admissions in some departments, believe explicitly or implicitly that mathematical ability at the level required to be a top mathematician is mostly fixed by the end of undergraduate education, and that mathematicians can recognize such ability with high accuracy.

The logical corollary of such a belief is that people who did not gain admission directly to a top PhD program with their BA/BS most likely do not have such ability and hence should not be admitted. Most applicants with a Masters degree in the US ended up in an MA/MS program because they did not manage to get into a PhD program, and most of the rest are in a non-top program and trying to get into a top one.

In other words, some people consider a US Masters degree a negative signal that you are not(*) good enough to have gotten into a good PhD program right after undergrad. (Of course, if your undergrad degree wasn't in mathematics and you solve a well-known-in-its-subfield 30 year old problem while working on your Masters, that's a stronger positive signal of your ability. (This is a true story.))

Such attitudes have discriminatory effects against people from various disadvantaged backgrounds (including almost all women), which I note here but don't want to get further into.

(*) I want to point out I did not write "were not".

Answer 3

I expect that your "slight feeling" comes not so much from the university itself as from its recruiters. If the university is trying to attract students, it will naturally prefer to have them for a longer program as well.

American students frequently earn multiple degrees. It is not uncommon to have master's degrees in addition to doctoral degrees. In terms of acceptance to a program, the more important point may be the scholarship which the potential student has maintained throughout his or her prior academic career, including the GPA for the master's degree(s). This is important, not for its indication of mastery level so much as for its predictive value to the diligence and study habits of the student.

Ultimately, it boils down to this: Universities like to have quality students who will well represent them in the future. When one has studied for a longer term in an institution, one also tends to have built a greater loyalty to it. It is, therefore, advantageous for the university on multiple counts to have longer-term students.