What is this career path?
In this profile we focus on doing a Computer Science PhD in the US, which usually takes 5-7 years. There is relatively low emphasis on taking classes – typically you only take classes when they are relevant to your research, and these can be in disciplines outside of computer science, including statistics, operations research, maths, psychology and linguistics.1 The PhD is heavily research focused – by the end you write a dissertation which is a long and in depth exploration on a topic that you become an expert on.
Why do a computer science PhD?
You learn cutting edge research skills
The most commonly cited advantage of a computer science PhD is that you learn highly advanced research skills:
- You learn the skill of choosing promising areas of research that are at the edges of a field: “Doing a PhD will force you to cast away from shore and explore the boundary of human knowledge. There’s a real trick to picking good problems, and developing a taste for it is a key skill if you want to become a technical leader.”2
- You become fluent in both written and verbal technical communication: “I’ve noticed a big gap between the software engineers I’ve worked with who have PhDs and those who don’t in this regard. PhD-trained folks tend to give clear, well-organized talks and know how to write up their work and visualize the result of experiments. As a result they can be much more influential.”3 This is a skill that’s important for entering data science.
- You learn to run experiments and interpret the results and get every aspect of your methodology closely critiqued.
- You learn how to read and critique research papers.
Potential for large impact from research
- During your PhD you get to work on the hardest problems at the edge of human knowledge, in a field with a strong track record of transformational research, in spite of its short history as an academic discipline. “PhD research is about opening up new avenues of enquiry, and working on problems that the rest of the world hasn’t even articulated yet. If you do it right, you can have tremendous impact.”4 A computer science PhD opens up the potential to carry on with this research in academia or in industry.
- You have lots of freedom over what research topics to work on during your PhD (though if you want to continue to academia, you’ll need to initially focus on the topics that will most aid your career).7
- Artificial Intelligence is one of the most important trends of the next century and is currently the most popular area of specialisation among computer science PhD’s.5 We think it’s especially important that more people work on making sure the development of AI is done safely, and there’s increasing funding available for researchers with this aim, making it a promising area to enter. A computer science PhD opens up jobs focused on AI safety in industry (for example at DeepMind), non-profits such as the Machine Intelligence Research Institute, and academia. If you want to work on this research, see our full review of the area.
- You often become the leading world expert on the area of your dissertation.
- You gain a much deeper understanding of complex computer science topics, which can help with reaching technical leadership positions in industry, which are in-demand and well-paid.6 People with PhD’s also frequently get more freedom in their subsequent jobs than those with bachelor’s or master’s degrees.7
- Highly intelligent peers, and close mentorship and feedback from some of the smartest people on earth.
- PhD level research can be extremely satisfying. You can discover previously completely unknown knowledge, you gain deep understanding of your area and you get to prioritise accuracy and truth over functionality and speed much more than you do in industry.8
- It is generally easier to move from a computer science PhD into industry than it is to move from industry into a PhD.9
Reasons not to do a computer science PhD
- It takes a long time: “Nobody finishes in four years. The typical time to completion is around five or six years, but there is a long tail — I reserve the term “paleo-student” for someone who has been at it more than 10 years.”10
- You don’t get wide exposure to different career areas during this time – you only learn about academic computer science.
- Currently only around 30% of computer science PhDs get jobs in academia, with less than 10% getting tenure track positions.11 To get a tenure-track position it is increasingly necessary to do one or more post-docs first, meaning you face even more time with relatively low pay.12
- Currently only around 55-65% of those who get jobs in industry after their PhD get research positions (suggesting it may have been better for them to enter industry directly).13 Overall, only around half of computer science PhD’s get research positions immediately after their PhD’s whether this is in academia or in industry.14
- The PhD is extremely unstructured – you do highly open-ended research with no clear guidelines on progress or how to organise your time. “Research can be very rewarding and very frustrating. Most students describe graduate school as a roller-coaster with tremendous highs and tremendous lows.”15
- The pay is not that high – median stipends range from $17,000 to $29,000.16
You need an undergraduate degree in computer science or a closely related field like engineering, maths or physics (or another major as long as you took a lot of CS classes). A master in computer science can help you enter if your major wasn’t in computer science and you haven’t taken many CS classes.17
You also typically need:
- Previous research experience
- Excellent letters of recommendation from researchers who can comment on your research ability
- A high GPA (3.5-4.0) in computer science and maths classes and quantitative reasoning GRE scores over 650.18
Who should most strongly consider a computer science PhD?
You should only consider a computer science PhD if you are incredibly motivated to do high-level computer science research. All the advice we read was emphatic on this point. Here is a representative quote:
The only reason to do a PhD is because you love doing research. If you don’t love research, don’t bother — it is not worth the time, money (in terms of opportunity cost vs. making a real salary in industry), or stress.19
Given that only 10% end up with tenure track positions and of those that enter industry immediately after the PhD only 50% end up with research positions, it’s unclear whether the PhD is worth the considerable costs for the bottom 50% or so of candidates.
Overall, especially consider a computer science PhD if:
- You meet the entry requirements.
- You’re highly motivated to do computer science research.
- You expect to be among the top 30% of PhD candidates.
- You want to go into computer science academia or do high-level research in industry, especially if you want to work on artificial intelligence.
Notes and references
- Further reading
- Our wiki on computer science PhD's
- Computing Research Association Taulbee Survey on enrollment and employment of Computer Science PhD’s in North America
- Our profile on AI risk research.