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From The Faculty Chair

Six Thousand and Climbing?

Stephen C. Graves

Two years ago, my predecessor as the faculty chair, Steve Lerman, wrote a column for the Newsletter titled "Rethinking Graduate Enrollment." [Vol. XIII No. 3, January/February 2001.] He observed that the number of resident graduate students had increased from 4854 students in 1991 to 5566 in 2000, an increase of nearly 15%. He went on to develop a very compelling argument that we should impose a greater control on graduate enrollments, and in particular, that we decrease the number of students as a way to improve both the quality of the students' educational experience as well as the quality of life for the faculty.

I found myself in agreement with Steve's thesis. Yet since that time, the number of graduate students has continued to grow by another 500 students and we now have over 6000 graduate students. The undergraduate numbers have remained flat between 4100 and 4200 students. Whereas I had always thought of MIT as having one graduate student for each undergraduate, we now have a 3 to 2 ratio. And, I am told, the number of graduate alumni will surpass the number of undergraduate alumni in the next few years.

What is driving the steady increase in graduate students? And should we be concerned? I expect we first need to understand what the drivers for this growth have been before undertaking any discussion of how to limit or control the growth. Over the past year I have heard three hypotheses as to why the enrollments have increased.

One hypothesis is that the research environment on campus is much stronger and healthier, leading to a need for more graduate students. The argument goes that research volumes are up, due to a variety of factors. Over the past five years we have hired a large number of new young faculty into the slots vacated by the early retirement program; these new faculty have very active research programs. Another factor is that MIT has lowered the cost of a graduate student by restructuring the cost of an RA, eliminating summer tuition, and increasing the number of presidential fellowships.

A second hypothesis is that new Masters programs are primarily driving the growth. The Engineering School has introduced the MEng degree, now offered by several departments. Sloan continues to increase the size of its MBA program. And then there are the three-letter acronym programs – LFM, SDM, TPP, CMI, SMA – that result in more graduate students in one form or fashion.

The third hypothesis is that the time to complete a degree keeps increasing. Consider a doctoral program that once took four years on average; if it now takes five years to complete, then there will be 25% more students if we keep the intake rate the same.

To try to explore these hypotheses, I asked Lydia Snover from the Provost's Office for some help. Lydia generously provided me with the enrollment numbers, as well as number of degrees awarded, by department, for the last 10 years. I attach three tables with summary numbers by school.

From staring at these numbers, I'll offer my armchair assessment of what has happened.

First, we see that over this 10-year period the number of graduate students increased by about 700 students, or 13%. The Center for Advanced Educational Studies (CAES) accounts for 85 of the additional students in 2002; these are non-degree students, and were not included in the 1993 numbers, so the true increase in graduate students might be closer to 600.

To get a very crude model for the number of graduate students I did a regression of the number of students (without CAES) against the number of degrees awarded; I found the coefficients for a linear model that minimized the sum of the squared errors. Admittedly I am ignoring all lag effects, as well as the fact that not all students are in degree programs or get a degree. The model is:

Total Graduate Students = 5.4*Total Doctoral Degrees + 2.0*Total Masters Degrees

At a rough level this seems about right as we might interpret the coefficients as the duration of the degree program. A Ph.D takes about five and a half years, whereas the Masters degree is around two.

From this crude model, one has some evidence that the growth is attributable to the Masters programs. Over this 10-year period the number of Doctoral degrees awarded declined slightly, while the Masters degrees awarded grew by more than 300 per year. If one were to believe this model, then this increase in the number of Masters degrees leads to about 600 more graduate students.

By looking at the school level, we can get a bit more insight as to what has happened over the last 10 years.

Architecture and Planning: There are about 100 more students, with virtually all of this growth occurring in Media Arts and Sciences. The growth is split between Masters and Doctoral students.

Engineering: The number of Ph.Ds awarded has been flat over the time period, whereas the school is granting about 150 more Masters degrees each year. The school has about 300 more students.

A major component of the growth is certainly due to the MEng programs in EECS and Civil and Environmental Engineering, and the professional masters degrees in the Engineering Systems Division (SDM, TPP). Indeed, all of the other departments in engineering either have had a constant number of students, or actually a decline in numbers since 1993.

I suspect that some of the growth is due to increased time to degree for Doctoral students. I don't have hard evidence of this but only hearsay. But if the average time to degree had increased by one third of a year, which seems quite plausible, then this would account for 75 more students.

Humanities and Social Sciences: The number of graduate students has actually fallen by about 60, with much of this occurring in Political Science and a smaller decline in Economics. But the number of Ph.Ds awarded each year has fallen even more sharply, suggesting that the time to degree has increased over this time period. Thus, there might have been an even greater decline in the number of students, if not for the growth in the time to a degree.

Management: Sloan is awarding about 100 more MBAs each year, which results in about 200 more graduate students, relative to 1993.

Science: The number of graduate students has declined by 7% since 1993, and the throughput, in terms of degree granted, has fallen even more. As with Humanities, it seems that the time to degree has increased over the last 10 years. My "eye-ball" estimate is that the average time to a Ph.D has increased by a half year from around six years in 1993 to now up to six and a half years in 2002. Without this increase, I'd guess there would be 80 to 100 fewer students in the School of Science.

VP Research: The numbers here reflect the students in Health, Science and Technology (HST), the Operations Research Center (ORC), and up to 1998, the Division of Toxicology. The number of graduate students has almost doubled since 1993. But this is somewhat misleading as this increase is entirely due to HST, which has increased from 166 in 1993 to 322 in 2002. My understanding is that most of these students are in non-degree programs, so the actual impact is not as great as one might expect.

I close with three conclusions.

First, the growth in number of students over the last 10 years is primarily due to the Masters programs in the Engineering and Management Schools, as well as the new program in Media Arts and Sciences at the Media Lab. This part of the growth has been planned and is not the result of incremental decisions made by individual faculty or labs. This is not to say that we always made the right decisions when looking at a new program or initiative. But there was a process involving the administration and faculty that presumably tried to evaluate and weigh the costs and benefits of creating a new program or expanding an existing one. Nevertheless, if we want to control future growth in graduate enrollment, then we need to make sure that the evaluation process for new programs or initiatives properly accounts for all of the externalities from any increased enrollments.

Second, the time to complete a Ph.D seems to have increased over the past 10 years. Admittedly, from the data that I have, I don't have good measures of this. But the numbers from the Schools of Science and Humanities and Social Sciences certainly suggest that this is the case, and I suspect that this is also true in the School of Engineering. As a first step, I'd suggest getting better data so we can have a clearer picture of what has happened and possibly some understanding of why. Then, I'd think this should be an issue for the faculty, at least at a local level, as to how to get better control on the time to degree.

Third, I don't find much evidence to suggest that the growth is attributable to an improved or healthier research environment. The number of doctoral students seems pretty stable, while the number of Ph.Ds awarded has declined slightly - and this seems true across all of the schools. The efforts to lower the cost of a graduate student have been very successful in helping faculty with their research programs and activities; but this does not seem to be a major factor in increasing the number of graduate students. However, at least anecdotally, it makes it much harder to find a TA, as all the students are able to find RAs. And, I do understand that the number of postdocs has been increasing, which might be a topic for another column….

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