When I graduated from the University of California at Berkeley in 1997, non-California-residents made up about 10% of the undergraduate population [1]; the fraction now is 25% [2]. Here at the University of Oregon (UO), also a public university, out-of-state undergraduates are 44% of the student body. Why have these numbers increased so much at top state schools? The obvious, well-known, and correct answer is money. Non-resident tuition at UO is over three times larger than resident tuition ($35k/year vs. $11k). Out-of-state students are lucrative. It is often noted that the rise in non-resident student mirrors a decline in public funding for higher education throughout the US. Currently, legislators in California are considering requiring an increase in the in-state enrollment at UC campuses, capping non-resident enrollment at 10% in exchange for greater state support [3]. (The system-wide average is currently 19%.) I wonder if this will actually happen.
Given all this, I was curious: Does the fraction of out-of-state students at various “flagship” state universities correlate with the amount of state support? Or with the out-of-state tuition? I spent some time gathering data to find out. It’s cliché to write that the results were shocking, but I really am surprised by how this turned out!
Some of the numbers are nicely tabulated by the University of Oregon itself, whose institutional research site is quite good. This page shows state funding per resident student and resident tuition for all the public universities in the Association of American Universities (AAU), highlighting UO’s claim that Oregon provides an appallingly low level of support. I recommend clicking the link, but here’s a copy of the key graph:
Next I’ve plotted just the state support for resident student, ranked for the AAU public universities. This also includes the abbreviations I’ll use in all the plots below.
The range is amazing, from about $4k/student (Univ. of Colorado, Boulder) to over $31k/student (State University of New York, Stony Brook). UO is the second lowest, getting $6k/student from the state of Oregon.
Note that the overall height of the bars in the first graph is a measure of the total funds associated with a resident student, if one doesn’t account for other sources of revenue, like non-resident students. With this, would the bars be equal?
I searched for the fraction of out of state undergraduate students, and the out-of-state tuition, at all these universities. I picked 2018 a the year to focus on — the trends are pretty stable, and last year may be odd due to the pandemic. I wasn’t completely consistent — for some datasets I landed on 2017-18, for some 2018-2019, and for some I couldn’t find either and settled on something close by. Also, most sources included fees and tuition together, but I didn’t always verify this. (This took long enough as is!) There’s therefore probably a few percent uncertainty associated with all these numbers. I provide a spreadsheet, with all the sources (with URLs) here.
Now for the graphs!
Actually not quite: if you’re unaware of my book announcement, I encourage you to click here. (I just sent in my review of copyedits today!)
Now for the graphs, really!
Is out-of-state fraction correlated with state support?
I plot the fraction of out-of-state undergraduates versus the funding per resident student provided by the states.
Are they correlated? It looks like “no.” There’s a cluster around 20% out-of-state, and a cluster at 40-50%, but no obvious trends overall, or in either group.
Is in-state tution correlated with state support?
The graph:
There’s a trend, but it’s weak. Increasing state funding from about $10k/resident student to about $20k/resident student lowers the resident tuition from about $13k to $11k per year (fitting a line to the cloud of points). In other words, an extra $10,000 per student from the state lowers the student’s fees by $2000. (I find this amazing.)
Is out-of-state fraction weighted by tuition correlated with state support?
Perhaps the lack of correlation above is due to out-of-state tuition being different at different universities. A state with little state funding, for example, might have many non-resident students paying a bit more than the locals, or a few paying a lot more. Let’s plot the fraction of out-of-state undergraduates multiplied by out-of-state tuition versus the funding per resident student provided by the states:
There’s still not much to see. The schools are more clumped together in one bunch, but there’s still no trend. (The University of Michigan is quite an outlier, it seems!)
How different are in-and out-of-state tuition, by the way?
Let’s see:
On average, the out-of-state tuition is 3 times greater than the resident tuition. (Mean 3.0, standard deviation 0.5.)
What about the overall income from in- and out-of-state students?
How much money does an average student nominally bring in? “Nominally” means that this isn’t referring to how much students actually pay — there’s financial aid, grants, etc. We’re just considering the sticker-price of tuition, the flow of funds from the state, and the student population. Let’s look at the weighted average: the resident student pays the resident tuition, and is accompanied by money from the state; the non-resident pays the non-resident tuition. If tuition is $10k in-state, $30k out of state, the state provides $5k, and 30% of the students are out of state, the weighted average “money per student,” for example will be 0.7*(10k + 5k) + 0.3*30k = $19,500.
First I’ll plot it as a ranked list:

It’s a pretty wide spread, from about $20k/student (UT Austin) to about $40k (U. Michigan). I wonder why. In a rough sense, this “income per student” is also the cost per student. Why is the cost 100% greater in Michigan than Texas? (If I were a Michigan legislator, I’d ask this question, though I’d first check actual revenue per student.) UO is the fifth lowest out of the 28.
Next, I’ll plot this “income per student” versus the state’s funding per student. If the state funding simply makes up some fraction of some universal “cost per student,” these should be uncorrelated.

We find, however, a strong correlation! The states that spend more are funding universities that charge more, per student; the state funding is not offsetting the cost. (Note again the warning: this only applies to the sticker price. A real study of this would look into actual student-derived funds.)
Here’s another way to look at this: What’s the weighted tuition (resident fraction x resident tuition + nonresident fraction x nonresident tuition) vs. state funding?

There’s a weak downward trend, but less than I was expecting. A state that increases its funding per student from $10k to $20k, if following its peer institutions’ behavior, would induce a lowering of tuition by about $4k. (It would be better off just handing the money to the students!)
Conclusions
I was surprised by the results of this exercise.
Based on a simple analysis of easily accessible data, the relationships between how much states spend on their “flagship” public universities and how many out-of-state student they take, or how much tuition they charge, are not nearly as clear as one might expect. In fact, there hardly seems to be any relationship at all. Perhaps this is because tuition is a poor marker for student-derived revenue. I doubt this, though — at Oregon, real tuition income is a sizeable fraction of nominal income, if I remember correctly, and I doubt any of these universities are significantly different from each other.
Perhaps this means that though there aren’t clear trends between universities, there would be clear trends within universities — if California increases state funding, the UC system will lower the out-of-state student fraction. Perhaps this is true, especially in the short term, but the above graphs make me skeptical that UC won’t simply revert to the trends of other schools.
It seems that public universities set their costs, tuition, and student demographics roughly regardless of how much funding their states provide. Why is this? Why are some public universities so much more expensive than others? How do the legislators of various states weigh data like this? I don’t know the answers to these questions. I do know, however, that essays, articles, and analyses of this subject really should include actual numerical data. And even better: graphs!
Today’s illustration…
A lily I painted, based on one from “Contemporary Botanical Illustration”
— Raghuveer Parthasarathy, June 27, 2021
References
As noted, all the graphed data is here: https://docs.google.com/spreadsheets/d/1UdEysMZQYf6JFXk7-Y-CGt9AN39iml9uXMPzWrbxSdA/edit?usp=sharing If you want MATLAB code that makes the plots, let me know.
[1] The 1997 data is from page 35 of https://www.ucop.edu/enrollment-services//data-and-reporting/undergraduate-admissions/aa_final2.pdf, adding up the CA rural, urban, and suburban numbers to get 87.3%. For 1999, the earliest year for which data is provided at the UC “Infocenter” site, the non-resident fraction is 11.5% (https://www.universityofcalifornia.edu/infocenter/fall-enrollment-glance).
[2] UC “Infocenter” site: (https://www.universityofcalifornia.edu/infocenter/fall-enrollment-glance).
[3] Los Angeles Times, “A bold plan for UC: Cut share of out-of-state students by half amid huge California demand,” May 25, 2021. https://www.latimes.com/california/story/2021-05-25/bold-plan-for-uc-admissions-reduce-out-of-state-students