There is no universal answer to this question, but parts of the application matter in different ways.
What’s In A Ph.D. Application
The contents of a Ph.D. application are pretty consistent across schools:
- A transcript
- GRE scores
- TOEFL (Test of English as a Foregin Language) scores if you are an international applicant.
- A personal statement
- Letters of recommendation
- A resume
- A list of faculty you are interested in working with.
These are trying measure, roughly, how you measure up on the following axes:
- Academic achievement (Grades)
- Aptitude for CS (GRE, Grades)
- Language skills (GRE, TOEFL)
- Your ability to perform research (letters, personal statement, resume)
- Other relevant experience you may have (Letters, personal statement, resume)
Several professors have written about how different components of the application contribute to an admissions decision (See “Other Perspectives” below).
Opinions vary, but there is near-universal agreement on a two points:
Good grades and test scores are never sufficient to predict success in a Ph.D. program. How necessary they are is a point of some dispute, but bad grades and low GREs are a red flag.
Research experience (especially if it is successful) is the best predictor of success in a Ph.D. program. Given the definition of success given above, this is not surprising.
Evidence of successful research should show up in three places in your application: Letters of reference, the personal statement, and your resume. Since different professors might look for evidence in one of those components more than the others, you need to pay close attention to all three.
Beyond that, there’s a mix of views. Some professors feel grades are important, but others do not. Some value work experience more than others, etc. Since you don’t know who will be evaluating your application, all these factors are potentially important.
GPA and GRE: How good is good enough?
You need pretty good grades, especially in CS. Faculty should be pretty savvy about adjusting their calibration for where you went to school, so it’s hard to provide definitive numbers.
The only data I’ve been able to find this is from Duke’s Ph.D program (Ranked 25th in US News). The average admitted student has a ~3.6 GPA. Good, but not stellar. At top schools, that number would likely be higher.
To be clear: Straight As are not necessary.
Duke provides data about GREs as well. The quantitative scores are pretty high: ~168 out of 170. Verbal is a little lower. The data doesn’t include the analytical writing score, but based on my experience, ~4 is pretty normal for domestic applicants.
Keep in mind, you can successfully study for the GRE (I took probably 20 practice tests) and potentially increase your score.
Research: How Much is Enough?
Research potential is the most important factor in Ph.D. admissions, but it is often the hardest to measure, especially since many students do not have direct research experience.
So, you don’t need to have research experience per se. Instead, you can use a wide range skills and experience to successfully convey your research potential.
To illustrate, consider some hypothetical students:
- Student A attended a top research-oriented university, and participated in a research project that resulted in a high-quality publication. Her letters of recommendation affirm her important contributions to the project and her demonstrated aptitude and interest in research.
- Student B attended a large, second-tier school where faculty do research and worked on a research project without a publication. The letters describe the enthusiasm, their outstanding work on some course projects, and the writer’s confidence that they would excel in a Ph.D. program.
- Student C attended a small college where research is rare. They did exceptionally well in their courses and worked on some independent projects. The letters remark that they are a “once in 5-years student” for that department.
- Student D didn’t do very well in college, but in the four years since graduating founded a startup that did interesting, hard things, but failed for business reasons. The from professors are out of date and lack-luster. The newer letters are strong but provide no useful information about research ability, because they weren’t written by researchers.
All these students demonstrate some aptitude for research, but only Student A has a clear track record of successful research. Student A will almost certainly get admitted.
The others are strong applicants as well, however, because they’ve shown promise in successful research-adjacent activities. Competition for good Ph.D. students is fierce and Student A is pretty rare. So, schools spend a lot of time looking for good students who don’t fit Student A mold.
If you aren’t Student A, then your research statement and letters of recommendation are all the more important. They need to convey, in your words and your recommenders’, why you are likely to be a successful researcher.
Listing Who You Want To Work With
Give thought to the faculty you list on your application as potential advisors. Because of how Ph.D. admissions works, who sees your application can have a huge impact on whether you are admitted. One of the best ways to help ensure that the right faculty see your file is to list them in the application. This means you should pick those names with care.
CS Rankings can help you identify faculty in the right area. Then, poke around on their web pages and publication lists to see whose interests match yours. You can also talk to faculty at your home institution to try to identify the right people to list.
Video Answers To Related Questions
- What matters most in the application? Undergrad grades, graduate (MS) grades, GMAT/GRE, recommendations or research experience?
- How does work experience as software engineer factor in? Or does that only count if you’re part of a published research project?
- How important is it to reach out to potential advisors before applying? Can they vouch for you in the application process later on?
- Should I still apply if I don’t have any research experience?
- What’s the weight of different parts of the application (test scores, grades, letters, SOP, undergraduate research)?
- What are some of the qualities of an ideal candidate for a PhD? Conversely, what might raise a red flag in a candidate’s application?
- Should I still apply if I don’t have any research experience?
- Karthik Raghunathan’s essay on Ph.D. admissions provides a discussion of each component of our application.
- Section 3 of Applying to Ph.D. Programs in Computer Science discusses application components and their importance.
- Amin Vahdat’s thoughts on the whole Ph.D. application processor. Search for “Q: What does the admissions committee look for in a successful applicant?”
- Dave Anderson’s Reflecting on CS Graduate Admissions provide some perspective on how admissions works. Keep in mind that Dave is at at CMU (#1 in US News and #1 in CS rankings), so the criteria they apply are at the very extreme end of selectivity.