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Understanding the U.S. Domestic Computer Science Ph.D. Pipeline

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Understanding the U.S. Domestic Computer Science Ph.D. Pipeline, illustrative photo

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Recruiting domestic students (U.S. citizens and permanent residents) into computer science Ph.D. programs in the U.S. is a challenge for most departments, and the health of the "domestic Ph.D. pipeline" is of concern to universities, companies, government agencies, and federal research labs. In this column, we present results from two studies on the domestic research pipeline carried out by CRA-E, the Education Committee of the Computing Research Association. The first study examined the baccalaureate origins of domestic Ph.D. recipients; the second study analyzed applications, acceptances, and matriculation rates to 14 doctoral programs. Informed by findings from these studies, we also present recommendations we believe can strengthen the domestic Ph.D. pipeline.

While international students are—and will remain—crucial to the vitality of U.S. doctoral programs, an increasing number of these graduates return to their countries of origin for competitive job opportunities. The demand for new computer science Ph.D.'s is high. Currently, approximately 1,600 computer science Ph.D.'s are awarded each year from U.S. institutions, with approximately 55% of these Ph.D.'s hired by companies and federal research labs. Of the 1,600 Ph.D.'s, approximately 47% go to domestic students.1 Lucrative salaries and compelling jobs for new college graduates add to the challenge of encouraging domestic students to pursue a Ph.D.

A first step in understanding the pipeline of domestic students to Ph.D. programs is to examine baccalaureate origins of domestic doctoral students.4 This is the focus of the first of our studies, which found a relatively small number of colleges and universities are the undergraduate schools of origin for most domestic Ph.D. students. Specifically, for the years 2000–2010, just 12 schools accounted for 20% of the approximately 5,500 domestic bachelor's graduates who received a Ph.D. in computer science and 54 schools were the undergraduate origins for approximately 50% of domestic Ph.D.'s. Approximately 730 other schools were the origins of the other 50%; on average, these schools had less than one graduate every three years receive a computer science Ph.D.

To better understand the domestic student pipeline and ultimately make recommendations for how to improve it, we worked with 14 U.S. computer science Ph.D. programs that provided graduate admissions records during the period 2007–2013. This data, a total of 7,032 graduate admissions records from domestic applicants, formed the basis of our second study. The 14 departments ranked 5 to 70 (out of 177 graduate programs ranked) in the 2014 U.S. News and World Report (USNWR) ranking of graduate programs in computer science6 and during the 2007–2013 period they produced about 19% of all computer science Ph.D.'s in the U.S. For those 14 departments, approximately 35% of the Ph.D.'s are awarded to domestic students.

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Methodology of Admissions Study

Our admissions study partitioned the 14 departments providing admission records into those ranked 5–10 and those ranked 11+. We refer to these 14 departments as the consumers since they take students into their graduate programs. The institutions where the 7,032 students completed their undergraduate studies are called the producers. Approximately half of the 7,032 graduate records came from consumer departments ranked 5–10 and half from departments ranked 11+. We intentionally did not include admissions data to consumer departments ranked 1–4 since their graduate admissions profiles are significantly different (their acceptance rates are typically one-third of those for schools ranked 5–10).

Admission records are for domestic students having completed a baccalaureate degree at a producer institution. Each record includes the following information: the name of the producer school, year the student applied to graduate school, name of the consumer school the student applied to, decision of whether or not the student was accepted by the consumer school, and—if the student was accepted—whether or not the student chose to matriculate. The data also included gender, underrepresented minority status, GPA, and GRE scores.

The dataset has some inherent limitations. Admission records had no names and thus students who applied to multiple graduate programs produced repeated records. Records do not include important information used in the admission process, such as recommendation letters, statements of purpose, and research achievements. Finally, there is no way of knowing which applicants accepting admission actually did/will receive a Ph.D.

The 7,032 records came from a wide range of producer schools. To better identify and understand trends, we partitioned the producer schools into seven groups (listed in the accompanying table). We use a commonly used classification of institutions, the 2005 Basic Classification of the Carnegie Foundation,5 and the most frequently used rankings of CS departments and liberal arts colleges, the USNWR rankings.6 These seven groups capture over 91% of all applications.

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For the entire dataset, 35% of the applications resulted in admission. Figure 1 shows the admission rates from each of the seven producer groups (x-axis) to the participating consumers (graduate schools) ranked 5–10 and ranked 11+. While it is not surprising that schools ranked 5–10 have lower admission rates than schools ranked 11+, the disparity is particularly notable for producer groups RU/H and master's. For example, for students receiving their baccalaureate degree from an RU/H institution, admission rates are 9% for applications to departments ranked 5–10 versus 42% for schools ranked 11+.

Figure 2 summarizes the number of applications, admissions, and matriculations to consumer departments ranked 5–10. Figure 3 does the same for consumers departments ranked 11+. For example, 927 of the 7,032 records are from students with baccalaureate degrees from RU/VH-25 departments applying to graduate programs ranked 5–10. From those, 196 were accepted (21% acceptance rate) and 104 matriculated (53% matriculation rate).

Figure 2 shows that consumer departments ranked 5–10 have a matriculation rate of close to 50% or better for all producer groups, except for students from TOP25LA+ producers schools. Their matriculation rate is only about 28%. For consumer departments 11+, the lowest admission rate is observed for students from the master's producer group (39%). Admission rates are about 60% for students from TOP4 and TOP25LA producer groups. Matriculation rates range from about 20% (for students from the TOP4 and TOP25LA+ producer groups) to about 40%.

For 99% of the admission records the data included gender, and for 76% it included ethnicity. The percentage of female applicants was 14%, and the percentage of African Americans and Hispanic/Latino was 3% each. Comparing this to their percentage of Ph.D.'s awarded, approximately 17% of CS Ph.D. graduates in the U.S. are women, 1.5% are Hispanic, and 1.5% are African American.1

Our dataset showed some interesting trends with respect to gender and ethnicity. In particular, a disproportionate fraction of female applicants came from TOP25 liberal arts colleges, while a disproportionately small fraction of African American and Hispanic students came from these colleges. A relatively large fraction of Hispanic applications came from RU/VH-25 producer institutions, while RU/H and BAC-25LA were major producers of African American applicants.

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Observations and Recommendations

Looking at the baccalaureate origins of students in the domestic pipeline, a number of trends emerge. Master's institutions and departments awarding Ph.D.'s produce approximately an equal number of computer science bachelor's degrees.3 But the number of applications accepted for admission at Ph.D. programs ranked 5–10 from students who received their bachelor's from research universities was over 24 times higher than for students from master's institutions. The analogous ratio for the 11+ consumer departments was 4.5.

Members of graduate admission committees are, understandably, cautious about admitting students who do not appear prepared for graduate work, particularly if they have had no firsthand research experience. But talented students with potential for research exist in all producer groups. Consumer departments interested in increasing the number of domestic Ph.D. students, and producer schools wanting to better advise their students to be competitive for graduate school, should consider the following interventions and strategies.

Graduate admissions committees need to be realistic about their applicant pools.

Graduate admissions committees need to be realistic about their applicant pools. Applicants from TOP25 departments are highly desirable, and active recruiting from TOP25 departments may not be as effective as expected. Even for highly ranked Ph.D. programs, matriculation rates for these students are low.

Graduate admissions committees should also be aware of the breadth and differences of educational institutions in the U.S. Our findings indicate some large graduate schools have forged productive partnerships with colleges and smaller universities in their regions. These relationships can begin with a faculty member from the Ph.D. program giving a talk to undergraduates and faculty at prospective partner institutions, and it can evolve into summer and academic-year research opportunities for undergraduate students from the partner colleges and universities.

Producer departments should support and foster computer science student research communities and highlight student research achievements. One effective practice is to hold annual undergraduate research presentations and poster sessions and provide incentives (such as food and beverages) to attract younger undergraduates to see what their peers have done. Publicized recognition of undergraduate research achievements can also be effective.

Producer departments should hold periodic information sessions on careers in research, summer research experiences, and graduate school, and should invite researchers from industry and academia to speak with students about careers in research. Undergraduates—even those at research universities—often have misconceptions about research and graduate school.

Private and federal research laboratories can contribute to the health of the domestic pipeline by expanding the quantity and breadth of undergraduate research opportunities and encouraging summer interns to pursue graduate studies.

For all producer and consumer institutions, the Computer Science Undergraduate Research CONQUER website2 has valuable information and resources for supporting undergraduate involvement in research. This information can be useful in any student research environment, and in particular, it can be a resource to bring more students into the domestic Ph.D. pipeline.

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1. CRA Taulbee Survey;

2. CRA-E's Undergraduate Research Conquer website (CONQUER);

3. Hambrusch, S. et al. Exploring the baccalaureate origin of domestic Ph.D. students in computing fields. Computing Research News (Jan. 2013).

4. Hambrusch, S. et al. Findings from a pipeline study based on graduate admissions records. In Proceedings of the CRA Snowbird Conference 2014;

5. The Carnegie Classification of Institutions of Higher Education;

6. U.S. News and World Report. Computer science rankings (2014);

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Susanne Hambrusch ( is a professor of computer sciences at Purdue University in West Lafayette, IN.

Ran Libeskind-Hadas ( is the R. Michael Shanahan Professor and Department Chair of the Department of Computer Science at Harvey Mudd College in Claremont, CA.

Eric Aaron ( is a visiting assistant professor of computer science at Vassar College in Poughkeepsie, NY.

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The authors are members of the Computing Research Association Education Committee and gratefully acknowledge valuable contributions by Charles Isbell and Elijah Cameron of the College of Computing at the Georgia Institute of Technology.

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F1Figure 1. Admission rates of applications from the seven producer groups to consumer departments ranked 5–10 and 11+.

F2Figure 2. Number of applications, admissions, and matriculations to consumer departments ranked 5–10.

F3Figure 3. Number of applications, admissions, and matriculations to consumer departments ranked 11+.

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UT1Table. The seven producer groups.

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Copyright held by authors.

The Digital Library is published by the Association for Computing Machinery. Copyright © 2015 ACM, Inc.


Suzanne Matthews

The 17% number for women is a bit disingenuous. If you look at the Taulbee survey cited, that number represents all women who received PhDs from U.S. institutions, not just domestic women. The number of domestic women receiving PhDs is closer to 7%.

Ran Libeskind-Hadas

Thanks for your comment, Suzanne. Indeed, the 17% of Ph.Ds awarded to women refers to all degrees awarded - not solely to domestic students. There was no cause or intent to be disingenuous, but we see that the juxtaposition of this sentence and the previous one could be potentially confusing.

Suzanne Matthews

I realize now that my wording was too harsh, and apologize for it. I really appreciate that you and your co-authors are drawing attention to the domestic Ph.D. pipeline. I don't think many people understand how narrow it is.

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