Demystifying Graduate Admissions for Statistics PhD Programs

My previous blog posts (such as my post on navigating the tenure-track job market) have reportedly helped many individuals. I do love helping people and sharing insights about what I have learned. So in this post, I figured that I would help another segment of people: aspiring PhD students in Statistics! This blog post attempts to walk prospective Statistics PhD students through the process, so they can know what to expect and how admissions works. However, aspiring graduate students in other disciplines may also find this post useful. That said, there are likely a few things that are unique to the Statistics discipline. In addition, this post focuses on Statistics PhD programs in the United States (the process could be very different outside the U.S.).

Things to Know Before Applying

I have served on the Graduate Admissions Committee for several years now at my current department. So I have been involved with graduate admissions for a long time. A few comments are in order first.

Graduate admissions in the field of Statistics are decided by an Admissions Committee made up of multiple faculty members. This committee almost always includes the Graduate Director or Graduate Coordinator, in addition to other current faculty members.

In other fields, it is often strongly recommended that prospective students reach out to individual Principal Investigators (PIs) if they are interested in joining their lab. In these other fields, the potential PhD supervisor’s recommendation carries a great deal of weight, since the applicant would be joining the PI’s lab directly if they are admitted. However, in Statistics, first-year graduate students typically do not join a lab or pick a supervisor right away. Instead, these students take a year of courses and then take qualifying exams. Only after a student passes the PhD Qualifying Exam(s) are they allowed to choose a PhD advisor.

Because it cannot be determined which students will pass the PhD Qualifier, most individual professors will not accept applicants directly as their PhD supervisees or agree to recommend applicants whom they do not know for admission. Instead, in most cases, it is solely the recommendation of the Graduate Admissions Committee whether or not to admit a PhD applicant.

Generally, the only exception to this is if a current professor in the department actually knows the applicant well (either through mentoring them on research or teaching the student in their class) and writes a recommendation letter for them. In this case, their recommendation will of course be taken into strong consideration.

You may want to dispel the notion of “safety schools.” A department’s selectivity is largely governed by the number of funded spots they have available. In recent years, my department has tried hard to raise the stipends for existing graduate students. Therefore, we currently target six to eight new graduate students every year (PhD and Masters students combined).

In addition, there may be other circumstances that determine the acceptance rate. In the past year, the University of South Carolina (USC) Board of Trustees approved waiving the application fee for all graduate programs at USC. Because of this, the number of applications we received to our graduate program skyrocketed to over 420 applications. Since our department typically admits around 20 applicants, our acceptance rate this past Spring was around 5%. (When we charged an application fee, the number of applications was much fewer, and the acceptance rate was in the high 20s/low 30s.)

Given this, it is hard to identify any particular program as a “safety school” for PhD admissions. In fact, is quite common for applicants to be accepted to “better” programs but rejected from “lower ranked” ones. This scenario happens all the time due to various factors (e.g. limits on the number of available funded PhD positions, policies that vastly increase the number of applications, etc.). So applicants should not be surprised if this happens to them.

Despite this, it is the case that applicants can make a list of “target” schools. The less ‘prestigious’ a program is, the more likely it is that the admissions committee will consider strong Masters performance as “compensating” for possibly weaker undergraduate performance. Whereas highly prestigious programs may demand academic excellence in all previous study, less prestigious ones may be more inclined to accept students who excelled in their Masters and/or who gained solid research experience but did not do as hot in their undergrad.

The Initial Review of Applications

Shortly after the deadline, the Graduate Admissions Committee reviews the applications. In our department, the applications are scored on a scale of 0 to 10, with increments of 0.5. We mainly look for several things: 1) evidence of mathematical ability, and 2) research potential. The strongest applications we receive communicate these two aspects. It is helpful if the recommendation letters also discuss the applicant’s math/quantitative skills and their research potential.

Mathematical ability is normally assessed by academic transcripts, recommendation letters, and to a lesser extent, test scores. It is not necessary that the applicant have a degree in mathematics or statistics (although most applicants do), but they should have one in a quantitative subject such as Computer Science, Physics, or Engineering.

If the student has weak math grades in undergrad (too many B/C’s or even lower) and no Masters degree, then it might be difficult to gain admission. However, if the transcript shows significant improvement after freshman year or if the weak grades are from a single semester/year, then we do take that into account. In this case, it may be helpful if the applicant gives a brief explanation for this (e.g. dealing with medical/family problems, disruption from the COVID-19 pandemic, etc.), while also highlighting their improvement in later semesters in their application.

In addition, my department does take into account strong Masters performance. It is possible to be admitted to our PhD program if the applicant did very well in a Masters program in Mathematics, Applied Mathematics, or Statistics. Our bar for applicants who only have a Bachelor’s is higher (i.e. it is very difficult to be admitted if your undergrad GPA is much lower than a 3.5). However, if the Masters performance is very strong, then that can make up for a lower undergrad GPA. This is not the case at every PhD program, but my program does give consideration to this. So if your undergraduate performance is not so great, then you may want to consider getting a Masters first in order to demonstrate mathematical maturity.

There are of course some exceptions to this. Some institutions are known to have grade deflation (e.g. a strict policy that only a certain percentage of A’s can be given out, the top ranked student in his/her class “only” has an 83 out of 100, etc.). Some of these schools are known to the members of the admissions committee, but in case they may not be aware of such policies, it is strongly recommended that the applicant clarify this point in their application or have a recommendation letter writer explain these policies. In addition, if the GPA is difficult to interpret (for grade deflation reasons or otherwise), it can be helpful if the applicant lists their class rank, First Class Honors, etc. on their CV. Anything that can help to put the GPA in context is highly appreciated. Having a recommendation letter writer explain these things also adds credibility.

The second thing that we look for is research potential. Therefore, it is very important to convey interest in research and understanding that PhD study is about research in your statement of purpose. We do not expect applicants to know exactly what field of statistics they will do their dissertation research on. However, we do expect them to show interest in academic research.

So how can an applicant’s research potential be conveyed? It helps if they actually have research experience! It does not have to be Statistics research or necessarily research that has already been published. Some of the applicants we end up admitting have done research in pure mathematics, engineering/physical sciences, or public health. However, substantive research experience (in any discipline) through a summer REU and/or by assisting a professor on a research project is definitely viewed very favorably. Being a third author on a manuscript or publishing a paper in an undergraduate journal is also viewed positively.

For the most part, we do not care so much about the venue in which the applicant’s research was published. However, we do expect the applicant to describe clearly their contribution to the research and what they learned in the process. In this case, it can also be very helpful to have a recommendation letter from a research supervisor who can explain the significance of applicant’s contribution and their potential for PhD research.

So what if a PhD applicant does not have formal research experience? In some cases, an otherwise strong applicant may not have research experience and has been out of school for awhile, making it difficult for them to accumulate this experience. In this scenario, it it still very important to convey research potential. In particular, it may be helpful to discuss notable class projects and how these projects informed your interest in statistics research in your application. It may also help to obtain recommendation letters from professors for whom you did these class projects and ask them to discuss your potential for PhD research based on the projects you did for them.

Finally, the GRE is also considered if the applicant submits their GRE scores. The GRE is mainly used as a “sanity check.” GRE Quantitative scores that are too low may give us some pause. Some departments may filter by GRE (so scores below a certain threshold are automatically rejected) — however, my department does not do this. It is also worth noting that high GRE scores on the Verbal section or the Analytical Writing section are viewed positively. Most of the applicants have GRE Quantitative scores above 160, but it is far less common for us to get applicants with GRE Verbal scores above 160 or Analytical Writing scores of 5 or 6. So when we see an applicant with these types of scores, this actually gets noted favorably by the admissions committee.

Zoom Interviews

After each member of the Graduate Admissions Committee has reviewed and scored the applications, they meet to discuss the applications. Typically only applications that had an average score around a certain threshold are discussed. First, the committee may decide which applicants to nominate for additional scholarships or topoff awards. Secondly, individual committee members may decide to change their score after discussion. Finally, borderline applications may be discussed to determine whether to advance the applicant to the interview stage. After all the initial scores are finalized, we then move to the interview phase.

Not all Statistics graduate programs conduct interviews. At some schools, the admissions committee simply decides which applicants to send first-round offers to after meeting to determine their shortlist. However, in my department, we do conduct interviews with a “long list” of both PhD and Masters applicants.

Typically, the 30-40 PhD and Masters applicants with the highest average score receive Zoom interviews. The overall rankings may not change drastically after the interview. However, a stellar Zoom interview may push a lower-ranked applicant into the “first-round offer” category, while a poor Zoom interview may push an applicant out of the “first-round offer” category. In very rare situations, the interview gives a major “red flag” that causes the applicant to be deemed completely unacceptable. However, this is very rare.

These Zoom interviews typically last for 15 to 20 minutes. We do not “grill” the applicants about their technical knowledge or quiz them on their knowledge about statistics. Instead, in the first half of the interview, we usually ask the applicants questions specific to their CV/application (e.g. their work or tutoring/teaching experience, their research experience or research interests, etc.). If the applicant is looking to switch to Statistics from an adjacent field (like pure math, economics, or engineering), we may ask them why they want to study statistics. Or if the applicant is doing a Capstone project or writing a Masters or Honors Thesis, we may ask them about that.

The second part of the interview is usually reserved for answering questions that the applicant may have. It is crucial for the applicant to ask questions — ideally, specific ones about our department (e.g. Qualifying Exam, program structure, etc.). If the applicant does not ask us any questions, that may be viewed unfavorably and cause their application’s score to decrease. Conversely, if the applicant asks very thoughtful questions, the interviewer will take note of this and likely increase their individual score.

Therefore, to “nail” the Zoom interview for graduate school, you should certainly be prepared to: a) discuss your background, and b) ask good questions.

A week or so after the Zoom interviews are completed, the Graduate Admissions Committee meets once again to discuss every single applicant that was interviewed. Individual committee members may once again change their scores based on feedback about the applicants’ interviews.

First Round Offers and Waiting List

After the scores are finalized for a second time for the applicants who received a Zoom interview, the committee decides on whom to send first round-offers to. In all cases, the department has a target number of incoming students. And in most cases, the Graduate Committee expects that only a fraction of these first-round offers will accept the offer and matriculate to our program in the coming fall. This requires a bit of “guess work” based on historical yield. Based on past years, our department expects about 30 to 35 percent of the individuals whom we admit to accept our offer. Therefore, if we are aiming for an incoming cohort of six to eight students, we will likely send out around 20 first-round offers. This usually happens in mid- or late February.

The first-round offers are made to the highest ranking (say) 20 applicants. Meanwhile, everyone else that was interviewed remains on the “long list” (or the waiting list).

In late March and early April, we may have heard back from many of the first-round offers, and then there could be some movement from the waitlist. If a higher percentage of the 20 first-round offers have declined than we would like, then we will move down the “long list” in the order that they are ranked and send out more offers to other applicants on the waitlist. Often times, even many of those on our waitlist have already received a competing offer from a different program that they prefer, in which case, we would then move to the next available applicant.

April 15 is the “official” deadline that PhD and Masters admittees are supposed to decide where they will be attending in the fall. Some first-round offers hold onto their offers and do not decline us until April 15. As a result, there may be some last minute offers of admission sent out to waitlisted individuals around April 15.

I would say that if you are extremely interested in a particular PhD program but are on the waitlist, you should wait until April 15 to see if there is any waitlist movement. If it is April 15 (or one of the days leading up to it), the Graduate Coordinator may reach out to you to ask your interest. But if you have not heard back and you remain interested, then you should certainly reach out to the Graduate Director and ask for a status on your application. If the target class size has been met, then the Graduate Director may choose not to admit any more PhD students. In this case, all the remaining applicants will be rejected. However, it does not hurt to ask.

Furthermore, if you remain very interested in a PhD program but are waitlisted, you should periodically keep in touch with the Graduate Director. Consistently conveying this enthusiasm creates a positive impression and has the potential to result in an offer of PhD admission if there are still available funded PhD slots.

What If I Didn’t Get In?

Hopefully, you will have received a PhD offer that is acceptable to you by April 15. However, in the unfortunate event that you do not receive any offers, you should keep a few things in mind.

First, there is a lot of noise in the processs. While the Graduate Admissions Committee does its best to identify the best applicants, there is invariably some degree of subjectiveness by the committee members. And it is possible that we overlooked some applicants.

Secondly, it is competitive. As I discussed above, we interview 30-40 PhD and Masters applicants for 6-8 available slots. If we granted you an interview, then that means we found your application strong. The overwhelming majority of those whom we interview would be perfectly acceptable graduate students (unless there was a major red flag in the interview, but again, this is very rare). In most cases, the primary reasons for rejection are just “The applicant did not rank high enough” and “There aren’t enough spots left.” You should keep in mind that your chances of admissions are not based on how your application looks in isolation, but rather, how it compared to all of the other applications that we received.

Finally, it is worth figuring out any potential shortcomings in your PhD application. Maybe the application didn’t mention research enough. Or if you only have a Bachelor’s and your GPA is a bit on the lower side and your grades in math classes are subpar (with too many grades of B or C), then it might be worthwhile to consider doing a Masters degree first and then reapplying to PhD programs.

Strong performance in a Masters program can certainly boost an applicant’s chances, at least in my program and programs at peer institutions. There is no surefire guarantee that this will get you admitted, but it does increase your chances of getting admitted somewhere. If possible, obtaining a Masters degree from a reputable university in the USA or Canada is also recommended for international applicants from undergraduate institutions that we may be unfamiliar with.