Is a PhD the best next step?
Only seriously consider doing a PhD if you want to do excellent research in the next five years, and if the degree will likely be useful for you afterward. Strictly, the second part is optional. For instance, your goal might be to do expert research in underwater basket weaving and then spend the rest of your life as a professional cat masseuse, or maybe you’ve already had a long career and might retire after the PhD. There’s nothing wrong with that, and I know people who have made similar jumps, but you’ll likely be more motivated when the PhD is a stepping stone to other things you want.
It’s stupidly easy to want things, of course. I want to run fast, save the world, and make my dog famous on social media. The real question is whether you want something else more, and here it can help to reflect on what you will give up and what you will gain through the PhD.
What you could gain:
You’ll become the world’s expert in some research area.
You’ll contribute to basic and/or applied knowledge through your research and publications. This can be an important source of meaning not present in other jobs.
You’ll likely get to travel to conferences and work in an exciting, international environment.
You’ll have a fairly flexible schedule and the option for a comfortable lifestyle.
You’ll become incredibly good at teaching yourself new things quickly.
You’ll hone your writing, project management, presentation, and diverse technical skills.
You’ll learn how to ask questions and develop a sensitive b.s. detector.
Your degree can give you access to better jobs in many fields.
What you could lose:
People outside your field might not understand or respect what you do. In some cases, a PhD might not help you get the job you want at all.
You’ll probably struggle more in this position than in other jobs with gentler learning curves and more formal training. The frustration can be demoralizing to many.
A corollary of academics not always being good managers is that there can be a higher risk of finding yourself in an unhealthy work environment. (I can help you minimize this risk.)
There is almost always a financial opportunity cost, in that you could be making more money elsewhere, or investing in a career that will make more money in the long run. That said, I have found applicants often seriously underestimate post-PhD salaries, including in academia, while simultaneously being overly optimistic about livable stipends in graduate school.
The modest stipends can make it difficult to support dependents in graduate school or to handle emergency expenses.
You might get bored with your research, decide you don’t want to finish, and have little to show for your effort.
These are weighty matters, and you probably shouldn’t be certain about doing a PhD until you’ve found a specific program and eventually research group that appears to be a good fit. But if this list makes you feel queasy about applying, it’s good to pay attention to those feelings. You might be able to explore them partly by reading about or even starting the application process.
FAQ about PhDs in science and engineering
My focus here is on STEM PhDs in the U.S. If you’re new here, I’m a full professor and PI at a selective R1 institution (about me).
What are the alternatives?
Remember that a PhD isn’t the only way to do research: Another option is to apply for a “research tech” or “research analyst” position in an academic group, ideally one that you would seriously consider for your PhD. Although you’ll likely not be granted the same independence or receive the same mentoring as a PhD student, it can help you understand better what research is like. You’ll have an easier time identifying the research questions, methods, and specific groups you want to pursue. Many times these positions are posted, so you should inquire directly with labs that particularly interest you.
Many people ask if they should do a masters first. I don’t usually recommend this.
How much does a PhD cost?
A PhD should not cost money. There could be an opportunity cost, if you’d otherwise be jumping into a lucrative career. But you should be paid a livable stipend during the PhD and receive healthcare. PhD stipends are typically just below the standard living wages in many areas, but they can often be a little higher. Often it’s easiest to talk directly with graduate students about this when interviewing, and especially after you’ve received an offer. You might learn, for instance, that a car is really not necessary, that it’s easy to access university-subsidized housing, and so on.
I strongly discourage anyone from going into debt during the PhD or joining a program that does not pay their PhD students a decent stipend.
What do PhD students actually do?
Formally, a PhD student’s goal is to produce an acceptable dissertation or thesis in an acceptable time frame, which is typically five years in the U.S. (but see below). In STEM fields, a thesis usually contains an introduction, two to three research chapters, and a conclusion, but the format varies by field. The entire thesis is usually only read by a few people on the student’s dissertation committee.
This isn’t as sad as it sounds, because the real content of the thesis are the two to three research chapters that are nearly always submitted as research publications or papers to scientific journals, to be read by other scientists across the world. This submission might happen before the thesis; often some chapters are submitted before or some after. These papers are original research contributions, which is to say, the PhD student is the primary author of studies that makes discoveries about the world. The student’s goal is to show they can create knowledge in the form of these publications, or publication-worthy manuscripts. The PhD is effectively a certification that they’ve made contributions of this caliber.
What they actually do all day can vary tremendously
Often in the first year, they’ll be focused on advanced coursework to build their foundation. In that year they might pass a qualifying, preliminary, or “general knowledge” exam to advance to candidacy (i.e., they become candidate for a PhD). Sometimes this step requires the submission of a thesis proposal and assembly of a thesis committee of 3-4 professors, but the proposal can also come later.
Early on, PhD students often read widely to select a good research topic, often under the guidance of their advisor. They may do this later on, too, when a research project doesn’t work out: the very nature of research means they’re solving a problem which no one else has solved before, and this can be hard. They may need to pivot their work and scrap dead-end projects.
A large part of the PhD is about managing failure and being adaptable by learning new skills, sometimes skills that no one else can really teach them.
PhD students typically write up research chapters as papers as they obtain results, although there is typically a focus on writing in the last year.
Throughout this time, they’ll be attending and presenting at conferences, applying for fellowships to support their work, doing some teaching (potentially a lot of teaching if needed by the program to pay their stipend), and learning other professional skills such as peer review.
They’ll usually do all this as part of a research group, led by a professor who acts as an advisor (a.k.a. “Principal Investigator” or PI), that may contain postdoctoral researchers, staff scientists, other PhD students, and undergraduate researchers.
Usually when they have completed enough work, their thesis committee and advisor signal that they are ready to graduate. This means they schedule a date for the thesis “defense” (which is usually a formality in U.S. programs, though not always). The committee reads their thesis and usually requests minor changes that are submitted within weeks or months of the defense. Upon completion of an acceptable thesis, the PhD is formally awarded.
How long does the PhD in the U.S. take? I’ve heard it’s faster in Europe. Isn’t it better to go there?
PhDs traditionally take five years in the U.S. and closer to three to four years in Europe. But there is tremendous variability between fields, programs, and even labs. Certain types of research are very difficult to rush and might require several years of data collection before analysis. Other types of research are easier to accelerate. Your options thus depend on your scientific interests.
In most cases, you can aim to complete a PhD in four years, especially if you communicate these intentions early to your advisor and get their encouragement. Four years is customary for many programs (e.g., MD/PhD candidates often have four years for the PhD).
Frankly, I would discourage three unless you have a masters already and know exactly what you want to do. This brings me to PhDs from Europe: A three-year PhD often doesn’t result in the same level of maturity and skill as four or five years. Many PIs I know take this into account when interviewing people for postdoc positions, recognizing that PhDs from Europe may not be prepared for the same level of independence.
How hard is it to get admitted?
This is tricky to answer. Admissions rates are generally higher than for undergraduate degrees at the same institution, but the applicants tend to be much more self-selecting! I’d estimate that in the most competitive programs, the admissions rate might be 1 in 10. It’s usually higher. Some of this self-selection arises from early conversations between potential advisors and applicants. I will often tell applicants who don’t have an appropriate background that it would only be worth applying to my lab after they gain certain skills.
An important mindset shift is that PhD admissions do not require smarts so much as excellent fit with the research goals of the program. This again makes it important to read and assess fit early.
Do you need to pick your advisor before applying?
The answer is formally “no” in many programs, but in practice
I would not consider any program, no matter how prestigious, if you can’t find several faculty there with whom you’d be delighted to work. This means you’ve read their papers, are excited about their research, and have talked to them. (There’s really a much longer process for selecting labs, which I detail.) I have seen students join ultra-competitive programs and then realize they had no good path forward because they hadn’t looked for a good fit between their research interests and those of the surrounding faculty.
Even in programs with rotations, it can often be customary for applicants to talk with potential advisors to assess research fit before applying. This can make a huge difference in getting your application noticed too.
Unless a program or professor specifies on their website not to contact potential advisors, you should plan to reach out to potential advisors several months before the application deadline.
How do I get in? And not regret succeed as a PhD researcher?
I’m currently working on tools to help PhD students be happier and more productive. But a great deal of happiness depends on approaching the PhD, and especially the selection of the advisor and program, the right way. I give my best advice here. You can also check out my free articles and follow me on Reddit and Instagram. I’m currently less active on Bluesky, but with enough followers, I’d be happy to pick it up again! Finally, I’d always like for people to email me (stemphdmentor@gmail.com) if there’s something they’d like me to write about.