How do you think about acceptance rate?

I’ve been playing around with IPEDS data and I pulled the top 10 schools by selectivity:[1]

school_name applied admitted enrolled acceptance_rate yield
California Institute of Technology 16626 448 224 2.7 50.0
Harvard University 61221 1984 1646 3.2 83.0
Stanford University 56378 2075 1736 3.7 83.7
Columbia University in the City of New York 60879 2404 1540 3.9 64.1
Massachusetts Institute of Technology 33767 1337 1136 4.0 85.0
Yale University 50060 2289 1554 4.6 67.9
Brown University 50649 2562 1717 5.1 67.0
University of Chicago 37522 2039 1729 5.4 84.8
Princeton University 38019 2167 1499 5.7 69.2
Duke University 50016 3174 1745 6.3 55.0

That’s a pretty good list of schools! Obviously there are many factors students should consider, but it seems like acceptance rate is a good place to start when ranking schools.

On the other hand, I’m not sure there’s much difference between CalTech (2.7%) and MIT (4.0%). Both are great schools and a student who gets into either one will have an opportunity for a great education. A resume with any highly selective school will have an edge (in theory) no matter the exact percentage of applications that were selected for admission.

So how do you think about acceptance rate when evaluating schools?


  1. I eliminated the top two schools for reasons I discussed on my site ↩︎

Is there a particular purpose in ranking by acceptance rate? That’s not all there is to selectivity.

Think about acceptance rate by the individual student’s application round (EA, ED1, ED2, RD, and in-state vs out-of-state for publics though none are on this list), if the information is available or possible to compute from publicly-available data.

If you are considering yield, that will also differ by application round.

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For our family, low acceptance rate does not = “it’s a college that our kid should attend.” Those schools have a vibe that doesn’t work for my kids. A bigger factor for our family is affordability. And we can’t afford any of those colleges, so we don’t even consider them, don’t go to visit those schools, etc.

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What factors are you thinking of? I’m looking at SAT/ACT scores[1] which gives an idea of academic standards. Is there something else to consider?

Sure. Those are different numbers and might be important when it comes to strategy around applying to schools. But I don’t think it matters much when it comes to how the general public thinks about these highly selective schools. A student who takes advantage of EA looks the same in the end as a student who transfers in as a junior.


  1. Though the test-optional trend shakes that up. ↩︎

Absolutely! That said, I have friends and family whose kids got into very selective and very expensive schools who make it work with scholarships, loans and other financial aid.

But yeah. Vibes matter. :slight_smile:

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If you consider test scores, then you must also consider % of test submitters. And you might consider the size of spring freshman entrants, which are not included in the reported stats, as well as any other missing groups, e.g. internationals, if the school doesn’t include them.

I get that you are simply playing around with IPEDS. But, trying to rank is quite the can of worms. There are a million ways to rank.

Furthermore, note that public perception is not the same thing as employer perception. And then there are different employer perceptions in different fields, and on and on…

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Yep. One of D19’s friends graduated Cal this year, after dropping out of a CSU then spending two years at a CC before transferring in. The diploma is the same. As you may have gathered, she would never have been in the running for a direct admit out of high school. That of course lends a whole different angle onto acceptance rate than what you’re looking at.

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Exactly! That’s sorta the attraction to acceptance rate for me. It’s a rough estimate of the reputation of an institution that’s easy to explain/justify. If it’s “good enough”, I don’t need to spend a lot of time working on something else.

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Mathematically, the acceptance rate is obviously a function of the number of people who apply and the number of people who are accepted. But not every applicant applies to every college, indeed even the most popular colleges only get a fraction of the total pool applying to them.

So given that people choose which colleges to apply to, what does a relatively low acceptance rate actually mean? In some sense, it is going to be as much, if not more, about the choices (some) people are making when choosing which colleges they will apply to, rather than the colleges themselves.

With that thought in mind, this is a bit complicated, but:

If admissions were perfectly predictable, there should not be low acceptance rates anywhere. It wouldn’t matter whether it took very high qualifications to get admitted, you would know what it took, and you wouldn’t choose to apply if you didn’t have those qualifications.

Of course they often aren’t perfectly predictable, and sometimes in fact they are quite difficult to predict once you have competitive qualifications. That is an important qualification, because there are often lots of people who realistically do not have competitive qualifications for a given college. And usually they simply don’t apply.

OK, so when there is some uncertainty about which applicants with competitive qualifications will get accepted, it makes sense there would be less than a 100% acceptance rate. And the more unpredictability among that competitive group, plausibly the lower the acceptance rate might go.

OK, so pausing here, so far we have a case for acceptance rates essentially being a measure of unpredictability of admissions among well qualified applicants. And that is not in fact the same thing as a measure of which colleges have the highest standards, which are the best at educating people, or anything like that.

OK, then for complicated reasons I won’t elaborate on unless asked, I think the practical limit for this sort of effect is probably somewhere around a 15-20% acceptance rate. Meaning beyond that point, I think in practice it starts becoming implausible that lots more truly competitive people are applying, and instead the dominant effect is lots more non-competitive people applying.

So why would so many non-competitive people apply to some colleges rather than others? I think the most obvious answer is they essentially see it as a type of lottery ticket.

The basic model in question is that even though the odds are extremely low, you see the payoff as being extremely high, and that combination makes you see it as worth trying. As an aside, there is a well-known effect where once people are convinced it is worth going for something of this form, they can start persuading themselves maybe the odds are not so bad, or maybe they can somehow shade the odds in their favor. And sometimes that gets into something sometimes called “magical thinking”. But to be fair, sometimes lottery-type bets are rational, if the payout is high enough relative to the odds.

So, rational or not, I think usually an acceptance rate much below 15-20% is good evidence that a lot of non-competitive applicants are treating this application as a type of lottery bet. And that implies they see a very large difference in value between these colleges and whatever colleges they would actually be competitive for.

OK, so why might some people perceive such a large value gap? I think at that point, it is many different stories. In some cases it might involves peers, family, local culture, or so on. In some cases it might involve beliefs about possible career outcomes. In some cases it might involve beliefs about cost. In some cases, there could be a feedback loop where they believe lower acceptance rates mean higher value. And so on.

Personally, I think often people like this are making some form of mistake, not realizing there are in fact colleges where they could be competitive that are not as far away in terms of true value as they think. Not that they can’t value some colleges more than others. But when they see such a big gap between a few colleges and all others, then I get suspicious they are not seeing the full picture. Or maybe are just VERY influenced by peers/family/etc.

But that doesn’t really matter, what matters is they BELIEVE these particular colleges are lottery tickets, and so they toss in applications to these specific colleges, and not others, despite being non-competitive.

And there is no real lower bound to that effect in my view.

OK, so that’s my view. And all the colleges on that list are well below that 15-20% line, so I think there is very likely a large lottery effect in play (and to be clear, I think there could be some lottery effect above that, I am just very confident the lottery effect is strong below there).

Some last bits of commentary.

On the plus side, I think if you actually are competitive for those colleges, those numbers don’t really mean that much for you. To be sure, even if you are very well-qualified, you might not be in any better shape than 15-20%, and there is enough dependence you could get blanked by all such colleges even if you applied to a lot of them. But I am not sure it is really much worse than that–if you are actually competitive.

On the minus side, what it REALLY takes to be competitive for these colleges is probably misunderstood by a lot of the people applying. And in fact, if you sort of started with the view one or more of these was a lottery ticket school, and then convinced yourself you should apply, you might be one of those people who starts rationalizing that you are more competitive than you really are.

Meanwhile, I think there are lots and lots of great colleges that fall somewhere in that 15-20% range, or indeed quite a bit higher, that simply do not experience the same lottery effect because so far fewer people see them in the same way as the lottery ticket schools. Value them more? Yes. To lottery-like levels, no. Indeed, not to be snippy, but their target markets may mostly be too knowledgable about US colleges to buy into a lot of that lottery type thinking. Like, as in, maybe they went to one of those perceived lottery ticket colleges themselves, and didn’t experience a lottery effect, so know better.

Still, I guess you could see that as a wisdom of the crowds issue. But again personally, I don’t buy it, I think most of the people who see some particular set of colleges as unique lottery ticket opportunities are making a mistake of some sort.

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My suggestion is if you want to use it this way, you do so inclusively and not exclusively, and also non-conclusively.

Like, using my framework above, I agree you can rationally conclude this means a lot of people see that college as a lottery ticket college. And you might well not believe that yourself (like me), but you could still think to yourself, “Well, lottery tickets colleges are probably at least among the schools that actually do provide a lot of value to students who can afford them, since otherwise they probably would not stay lottery ticket colleges.”

Fair enough, if that is what you are thinking.

But one obvious point is that just because a college has NOT experienced such a big lottery effect does not mean it could not ALSO be providing a lot of great value to its students. So, even if you see this lottery effect as evidence those colleges should be included on some prima facie “good colleges” list, I would suggest not concluding all good colleges therefore must experience the same large lottery effect.

The other obvious point, already mentioned by others, is that some, or indeed all, of those colleges could be bad for YOU, even if they are good for a lot of people. Again, in the end, even the most popular colleges only get a fraction of total applicants. So the truth is most people have decided not to apply to any given college, likely for good reasons in most cases.

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Except that some institutions seem to purposely manipulate this just to catch people who use this as a proxy.

And then there’s just the issue of people can apply to unlimited colleges and it’s so easy with the common app, so there’s the mathematical effect of more applicants.

When D19 was looking at colleges, BU had an admit rate of around 22%, it’s half that now. Do you think the college is twice as good as it was five years ago? Or, when my generation went to college, HYP admit rates were around 20%. Are they multiple times better now than they were?

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And in addition to this, the US college system as a whole is very large, and yet these colleges are pretty small by most standards.

I think it is worth quickly reflecting on, say, what happens with Oxford and Cambridge. They admit by course so overall acceptance rates are not terribly meaningful.

But Oxford, for example, publishes statistics by course, and what they call the Offers rate for their courses is almost always higher, sometimes MUCH higher, than the acceptance rates at the most selective US colleges:

https://public.tableau.com/app/profile/sdma.oxford.university/viz/UniversityofOxford-AdmissionsStatistics2023ByCourse/Applications

OK, so what is going on? Well, first, in the UCAS system, you only get 5, and not 20, applications. So that is more incentive not to use up an application on a “lottery” ticket.

In addition, you can only apply to one of Oxford or Cambridge, not both. Again, that will cut the lottery ticket applications as well.

Finally, Oxford and Cambridge are actually decent-sized schools, and then the UK system as a whole is considerably smaller. Indeed, when I did the math, I figured you needed something like 20 or so of the most selective colleges in the US (I included some LACs, but no publics) to add up to the same fraction of the US system as Oxbridge make up in the UK system.

OK, so imagine you could say, only apply to 1 of those 20 or so colleges in the US. I suspect you would then see considerably higher acceptance rates at those colleges. Not super high. But more Oxbridgey than their current very low acceptance rates.

You are implicitly getting into why I think the practical lower bound on just unpredictability effects, absent strong lottery effects, is roughly 15-20%.

Again, not that there no lottery ticket applications to HYP and such back in my day. But not nearly so many. And if anything, it was even harder back then to get good information on who was actually competitive for these colleges.

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Absolutely. I think part of the design of UCAS like that is exactly to limit acceptance rates from getting ridiculously low, in general and at Oxbridge. They also have a limit of 4 applications for medicine, I think there the idea is that students don’t get completely squeezed out of Uni options by only choosing a highly competitive course.

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It would take a lot to make this happen, but if acceptance rates keep dropping, I do wonder if at some point there will be a movement to overhaul the US system.

Like, possibly something like the UK system, but also whatever US colleges wanted to could voluntarily switch to a matching system like the NY high school, medical residency, or Questbridge systems.

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By itself, it is not that informative without knowing how strong the applicant and admit groups are.

Also, note that many colleges have different admission buckets, such as by major, so overall college admission competitiveness may not match that of a particular major. Other buckets could include automatic versus competitive admission applicants (e.g. at UT Austin and other Texas public universities).

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There are a few lower admit rate schools in IPEDS. For example, Minerva is listed as 208/20,816 = 1% admit rate. However, I’ve read that Minerva takes steps that artificially decrease admit rate, particularly how “applied” means only completed the basic info from common app part, not finishing the other section of application outside of common app. Students who didn’t finish application may get a rejection letter. Other schools also take steps that boost application numbers, such as Colby with simple, no fee application.

However, I think the bigger issue is equating admit rate with selectivity. They are certainly correlated, but are not equivalent. Different colleges have different applicant pools, some of which are far more self-selective than others.

For example, Northeastern had an admit rate of 6.8%, and Northwestern had an admit rate of 7.2%. Northeastern had a lower admit rate than Northwestern, but I expect the overwhelming portion of forum members would say Northwestern is more selective than Northeastern, and with good reason. Northwestern kids are on average stronger academically, and cross admits overwhelmingly choose Northwestern.

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Apples to oranges. UChicago plays games to get those numbers, MIT doesn’t.

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Reminds of the Yogi Berra quote…

“Nobody goes there anymore. It’s too crowded.”

Acceptance rate is a crowd sourcing method of ranking. If students apply in these numbers, despite very low odds it suggests they see fit, value or opportunity. We can question validity or super impose our own personal biases but doing so would be like when Yogi Bear claims to be “smarter than the average bear”. The acceptance rates in general terms represent the broad, “average” or consensus perceptions or rankings.

I find wisdom in odd places.

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Yep. :slight_smile: I addressed that in my post on my site:

That makes a lot of sense. Yield (enrolled/accepted) gets at that, but I can certainly see how that might not be helpful either. It would be interesting to know the results of that sort of head-to-head matchup.

I’ve seen that anecdotally, but I wonder if there’s a way to quantify that. Maybe financial data?