There was a brief flurry of discussion yesterday kicked off by Matt Yglesias posting People Don’t Major in Science—Because It’s Hard, which more or less says what the title would lead you to believe (either title, since he’s blogging for Slate where they like to give pages titles that don’t match the post titles…). This was inspired by a National Bureau of Economic Research paper, the full text of which seems to be paywalled, sort of– they emailed it to me at my work address for free. And since I could get it, I figured I should dig into it a bit to see what it really said.

I’m not going to do this in the humorous Q&A format like I do for physics papers, for a bunch of reasons. Primarily that, on a quasi-aesthetic level, I found this pretty awful. This is mostly a matter of differing norms between fields– I’m sure that it’s perfectly within the normal style range for the intended audience, but coming from physics, a whole bunch of things about this made me twitch. I particularly hate the use of multi-letter variable names in ALL CAPS with sub- and superscripts: E(AGPAt**i,SCI) in the screenshot above, and that kind of thing. This somehow manages to combine the complicated index structure of high-level physics with the clumsy pseudo-word labeling of college frosh (I kept having flashbacks to lab reports that give Newton’s second law as “FORCE = Mass X A” and that sort of thing). Further heightening the first-semester-lab-report feel was the stubborn insistence on using quasi-mathematical notation in places where words would be clearer: “those who have STATEi =SCI and j*=SCI, those who have STATEi =SCI but j* ≠ SCI, and those who have STATEi ≠ SCI.” would be better written “Those who enter intending to major in science and graduate with degrees in science, those who enter intending to major in science but graduate with non-science majors, and those who enter intending to major in a non-science subject and graduate with a non-science degree.” But then, I say that as an outsider to the field– presumably, people working in this field are conditiond to expect the features I find awful, and would find my preferred versions painful to read.

Because of the dense notation, I am less confident that I’ve correctly understood this than with most of the physics papers I write up, and there’s only so much time I can put into deciphering this stuff. So this will be a little shorter and less conversational than my usual research write-ups. But we’ll do at least a few question-style headers for this, because I don’t want to completely subvert expectations…

What did they do?

This is an analysis of survey data from several years ago, taken from two classes of students entering Berea College, 655 of them in all. They were asked on entering college to predict the field of their eventual major (majors being grouped into seven categories), the likelihood that they would graduate with a major in each of the seven categories, the likelihood that they would drop out before graduating, their GPA in courses for each of the seven categories, and their annual income at age 28. These questions were repeated every semester after that, and the results correlated with the actual GPA and major of the students in question.

This analysis (they’ve published other stuff from the same data set) was to track the way students move between majors. To that end, they construct a mathematical model that takes the various survey responses as inputs, and uses them to generate aggregate probabilities for various major categories, that they can compare to data. Using that model, they can then try to tease out the effect of various factors.

What are the basic results of the survey?

They find that, in general, students entering college are roughly evenly distributed among the different major categories, in terms of what they say they intend to major in and what probability they assign to graduation in each category. There are two areas where their predctions are way off: Only 5.1% of the entering students expect that they’ll drop out before graduating (an average predicted probability of 13.4%), while 37.5% of them do, in fact drop out; and while 19.8% of entering students expect to major in a science field, only 7.4% of them graduate with science majors.

These two are not all that directly related, in that the dropout rate for students who enter expecting to major in science is not any higher than the dropout rate for students intending to major in other areas. The disappearing science majors are disappearing into other fields: while students entering with a stated intent to major in science say there’s a 60% chance they’ll graduate with a science major, the actual number staying in science is only around 45%. This isn’t made up by students switching into science, either– students with non-science intended majors give about a 6% chance of switching to science, while the actual number is around 2%.

This switching also happens pretty quickly. By the middle of the sophomore year, 90% of the students who will eventually graduate as science majors are saying that they’re going to major in science, and only 3% of those who will graduate with majors in something else say they’re going to major in science. Because of that, they take the midpoint of the sophomore year as the decision time when they draw up their model of student decision-making.

When they dig a little deeper, what do they find?

They look at the influence of a couple of factors to determine the effect they have on students’ decision to change majors or not: the average GPA and the average expected income. Most of the effort goes into talking about grades, and the income picture is kind of muddy (largely because they can’t match the predictions to actual income the way they can match grade predictions to actual GPA), so I’m going to mostly ignore the income effects.

What they see is that the estimated GPA for science courses drops dramatically from the start of the first semester to the middle of the second year: the grade students expect in science courses decreases by 0.18 grade points for the entire sample. For those who enter with an intent to major in science, this is even more pronounced: the average expected grad drops by 0.30 grade points over that same span.

This leads to what struck me as the clearest demonstration of anything in the paper, which is explained in the cryptic text screen-capped above: over the first year and a half, the students who leave science become much more like the students who never intended to major in science, in terms of GPA expectations. Students who enter saying they expect to major in science and eventually graduate as science majors come in expecting a science GPA of 3.63, and that prediction drops by 0.27, to 3.36. Students who enter saying they expect to major in something other than science and graduate in something other than science expect a science GPA of 2.77, and that drops by 0.066, to 2.71. Students who enter expecting to major in science and graduate as majors in something other than science start out expecting a science GPA around 3.53, and end up dropping by 0.61, to 2.92. Their expected grades go from pretty much the same as the eventual majors to pretty much the same as that of those who were never science majors, in just three short semesters.

So, this is what they use to say that students drop science because it’s hard?

It’s not the only thing, but it’s probably the cleanest single effect. They spend a lot of time putting togther a model and finding coefficients and doing t-tests. In the end, they conclude that the GPA estimate has the biggest effect on the shift.

The other big point in favor of that explanation is that once they have the model, they can input different initial grade expectations and see what effect that would have. If they replace the distribution of expected GPA that they see in the survey data from the start of the first semester with that from the midpoint of the second year, the fraction of simulated students saying they’ll major in science drops to 10.4%, much closer to the actual figure of 7.4%. This is also suggestive of grades being the main factor.

So, what causes the bad grades?

They attribute it to innate ability, more or less, casting it as a process of students learning that they’re not actually good at science after taking a couple of science classes and getting bad grades in them. They aren’t really able to do more than that with the data they have– they can’t tell whether it’s a matter of students losing interest in science because of lackluster teaching or bad experiences with faculty and other students, or any of the other factors people like to talk about. All they know is what the students predict for their grades, and what they actually get for grades.

This lack of information, along with the relatively small size, is probably the biggest weakness in terms of finding out what you’d really like to find out regarding major switches and the like. But that kind of fine-grained information would be really, really hard to collect, so it’s not too surprising.

Any findings that they spend a bunch of time on that don’t seem that interesting to you?

They go on at some length about the significant underestimate of the likelihood of dropping out, which I found kind of mystifying. Not the underestimate, but the amount of time they spend discussing it. It seems crashingly obvious to me that students entering college aren’t going to assign a high probability to dropping out– if they expected to drop out, why would they be there in the first place?

They also spend a bunch of time looking at the correlations between GPA expectations in different major areas, finding that students expectations regarding their science GPA is not particularly well correlated with their expectations about their GPA in other classes. I’m guessing this is important for consistency checking or something, because it doesn’t seem all that surprising or interesting otherwise.

Any features that jump out at you that they didn’t talk up?

Two things: 1) They have a table showing the probability of graduating with a particular major broken down by initial prediction of their major, where unsurprisingly, they find that on the whole, the most likely eventual major is the one that students predicted initially. This is particularly strong for the humanities, though– students who enter saying that they plan to major in humanities have a 56% chance of doing just that, and a 34% chance of dropping out. The chance of ending up in any of the other categories is minimal. This is far and away the strongest of all the categories they measure.

2) Scientists get cocky. When they calculate the grade expectations for the three groups of students mentioned above, they calculate the expected grade for all of the major areas. Students who intend to major in science and graduate with science degrees decrease their expected GPA in science classes, but increase their expectation in everything else. Meanwhile, students who switch out of science decrease their expected GPA across the board, and students who never intended to major in science in the first place don’t show much of a pattern in the changes of their expectations.

I thought that was kind of interesting. I’m not sure it really supports the make-Steve-Hsu-happy conclusion that scientists are just smarter across the board than everybody else (which I’m sure it will be used to claim by somebody), but it was something I noticed.

So, bottom line: Do students drop out of science because it’s hard?

That’s maybe a little stronger than is really justified by the data they present. I think they have a decent case that students drop out of science majors because they find that they’re getting bad grades in science. I don’t think that you can really use this to make a solid claim that this reflects a lack of ability or preparation on the part of those students, though. Not without looking more closely at the individual students and why they switched, anyway. I suspect it’s the most likely explanation, but you can easily construct horror stories that would explain the motion between majors without invoking innate ability or prior preparation.

Comments

  1. #1 steve?
    Ann Arbor, MI
    July 3, 2013

    I wonder how much of this dynamic is driven by pre-meds. At least when I started school, it seemed like everybody and their cousin planned to go to med school and then filtered into other things pretty quickly.

    There’s probably a good number of students planning to go into medicine who get a C in their first organic chem class who are then advised that their odds of getting into med school are pretty small. Once they realize they won’t become doctors, they switch majors.

  2. #2 Eric Lund
    July 3, 2013

    I wonder how much of this is a perception in our society that science is something smart people do. Berea College draws its student body primarily from Appalachia, which is not known for having a high concentration of brainiacs, so people from that region who go to college (especially a private school like Berea) are presumably among the smartest in their high school graduating classes. They may have been encouraged to do science. As you suggest, some of the students get a reality check that tells them they aren’t as smart as they thought. In other words, it’s not that science is hard, it’s that college is hard. That the switchers tend to lower their GPA expectations across the board is consistent with this viewpoint.

    Since Berea is a liberal arts school, they probably don’t have much of an engineering program (if they do, it’s probably a 3/2 arrangement with a school that’s better known for engineering). I have observed anecdotally here at State U. that quite a few would-be engineers give up the idea after discovering that they can’t hack the math. I don’t come into regular contact with pre-meds, so I can’t vouch for what’s going on there, but there may be some who wash out in organic chemistry or some other such low level class.

  3. #3 David
    July 3, 2013

    I agree with you about the writing style (neurologist here, so a different point of view), and that alone would have prevented me from spending time on it. Thanks for the careful analysis of this paper. Beats having to slog through it myself.

  4. #4 Chad Orzel
    July 3, 2013

    I think the pre-med/ pre-engineering thing is definitely in play as well. There are a fair number of students who go to college with the vague intention of being doctors or engineers, often because of family pressure, who quickly find out that they’d rather be doing something else.

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  6. #6 Frank John Lowe
    South Africa
    July 4, 2013

    Thanks for the paper well done.Thats why I haven’t done any off the above I Am a dreamer and just followed my head and heart and done very well for my self.Never stop keep on trying never give up.

  7. #7 The Phytophactor
    http://phytophactor.fieldofscience.com
    July 5, 2013

    As someone who has spent several decades disappointing science majors, it is my observation that intellectual ability is not the answer. However there is a wide gap between our expectations and student work ethic that ends up with students bailing out of a science major. To get the results we expect they have to work longer and harder than they wish to. If my observations based upon only a few thousands of students are correct, that they apparently can shift to other majors and be successful is another matter to consider.

  8. #8 Eric Lund
    July 5, 2013

    that they apparently can shift to other majors and be successful is another matter to consider

    It is definitely much easier to switch from a STEM major to a non-STEM major than vice versa. Science and engineering majors have much more stringent course dependencies than most humanities fields (obviously excluding the ones that make heavy use of languages other than English). While it’s still possible to complete some STEM majors in four years if you are taking Calculus 1 later than as a first term freshman, it’s much more difficult, especially at smaller colleges and universities which may only offer it once per year. Scheduling all of the required course sequences becomes increasingly difficult the longer you wait to take any of the freshman-level courses. It isn’t always easy to complete a STEM major in four years even if you pass (or place out of) Calculus 1 as a first-term freshman. Keep in mind that, especially these days, many students cannot financially afford a five-year plan.

    To take as an example my undergraduate program: You had to take freshman mechanics, then freshman* E&M, then a waves and vibrations course, and in parallel two semesters of calculus and a differential equations course, all before you can take any of the upper level courses. Those upper level courses included a two-semester quantum mechanics sequence, a two-semester lab course, and various one-semester courses. And this program was easy, in terms of scheduling all of these courses, compared to some of the engineering majors. Compare with, for instance, history of Western music. If you are splitting that into three courses, you’d probably have one course covering up to 1750 (Medieval/Renaissance/Baroque), a second covering roughly 1750-1880 (Classical/Romantic), and a third covering 20th century classical music. There may be some advantage to taking those courses in that order, but it’s not strictly necessary.

    *This was at one of the few US universities that encouraged people to take intro mechanics as first-term freshmen. Most places defer this course until the second semester/quarter, or at least encourage STEM majors to do so, to ensure that students have taken Calculus 1 first.

  9. #9 Lord
    July 5, 2013

    Rather than “science is hard”, it sounds like, “science is made hard”, since you don’t see such an effect among non science majors and it doesn’t require them to adjust their expectations, a filtering effect. This could be because without an advanced degree, it is relatively useless, whereas non science majors have broad use in disparate jobs unrelated to their majors.

  10. #10 Kaleberg
    July 5, 2013

    I don’t think it is “science is made hard”. Science and engineering have always had the problem that, unlike a lot of fields, it is hard to BS your way through a course. I always found my STEM courses tougher than my non-STEM courses, because I had to get the right answers for the former, while I could just formulate good arguments for the latter.

  11. #11 Ottavio Forte
    Boston, MA
    July 6, 2013

    I am a retired aerospace electrical engineer with this personal data to offer, as I entered an engineering college in NYC way back when. I entered college with the expectation of becoming an electrical engineer. I was doing ok with my pre-engineering courses, but when I took my ‘first’ electrical engineering course, analysis, it felt like ancient Greek to me, I had to drop the course to preserve the GPA. Since I was DETERMINED to become an electrical engineer I took the same course again the next term, and got a B in it. No place in the data of the article above the student’s personal traits, social and family factors enter the equations for the probability of dropping out of science or any other category. I was a plugger and a hard worker, when things were tough I did not surrender.

  12. #12 sushma gowds
    chembur mumbai
    July 6, 2013

    my parents where not allowing me to take a science stream
    what can i do i don’t know?

    • #13 Frank Lowe
      South Africa
      July 6, 2013

      It is Sad but I carried on by my self I am 64 and discovered a very big thing about Earth and Space.And nobody wants to listen to me because I haven’t got that degree or paper to prove I am a somebody.What I learned if you are too well educated you can not think stupid anymore and forget the basics and miss the point.Cheers

  13. #14 Lord
    July 6, 2013

    I think it every bit as possible to make all other majors just as difficult, memorization and style are a common ways, but we don’t because it is not felt there is any point to it. What would they do as an alternative? No one considers an over supply of humanists a problem. The degree is just a credential of passage. If it wasn’t made hard, their expectations would be similar to non science majors and closer to reality. The reason they aren’t is high school doesn’t see their function as filtering and these expectations are carried forward.

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  15. #16 evodevo
    July 7, 2013

    Berea? Really? That alone would skew the results away from science majors …. I can’t imagine getting a valid sample there. It was founded as a liberal arts, work-study kind of place, with an emphasis on Appalachian crafts, not one where I would expect to get a good background in ANY science field, and for that reason if I were planning on majoring in science, would not even apply there. EKU is just up the road, if you want a cheap undergrad degree in science.

  16. #17 Omega Centauri
    July 8, 2013

    Is there a breakdown between the more math heavy science and engineering, and sciences that are less so. Think Physics and Chemistry (and say mech engineering) versus say Biology and Geology. Many who start out in the former never really loved math, and probably had false expectations about their subject matter -more that 50% of the effort could be described as math. So they get beyond gee-whiz science, and either have to get good at math quick -or they bail to something that requires only minimal math.
    I also wonder how much (and how much longer) those less math-rich sciences, like biology and geology don’t require well above median math anymore? My guess, is the person who loves science but hates math, probably could have found a place in science several decades back, but is probably now out of luck.

  17. #18 Hyperion
    July 9, 2013

    One question that I would ask is how many of those people who switched from a science to non-science major and graduated then went on to work in a scientific field as a non-scientist (ie in a supporting role of some sort)?

    The reason I ask is because I can see an advantage in trying to keep these individuals interested in science. Those who go on to major in English might be able to make up for the dearth of good science journalists. Those who switch to a poli sci major (like myself) can help ensure that legislators and regulators and policymakers are implementing science-based public policy. I’m pretty sure that most majors can produce people capable of supporting scientific organizations and scientific research.

    I really do wish that there was more emphasis on helping people who switch out of a science major find careers tangential to science.

  18. #19 Eric Lund
    July 9, 2013

    @ΩC: Biologists need to know some statistics. They can probably get by in some areas without calculus (beyond what’s needed to understand statistics). With geology there are still some specialties that don’t require much in the way of math, but a lot of it these days is geophysics, and that does involve heavy-duty math.

    @Hyperion: I know anecdotally that some people who don’t have a formal science background work in science groups, but I don’t know how many of those are ex-science majors. I also don’t know how common it is. I suspect it’s less common than it would have been in the 1960s, because we are cranking out lots of science majors, too, and not everybody who gets a Ph.D. in science can go on to get a tenure track position.

  19. #20 CC
    candidcerebrations.blogspot.com
    July 10, 2013

    I think that the fact that science education has quite a different format than non-STEM majors plays a major role in why they are perceived as harder. My opinion is excluding engineering majors because usually they are very different from both the hard sciences and non-STEM majors in format.

    I recently graduated with both a STEM major and a non-STEM major. The path to getting these degrees were completely different. While I can only comment specifically on my university’s format, I do think (based on what I’ve heard from others) is that my experience can be generalized to other universities too.

    Majoring in science, one needs to take many general prerequisites outside of their field. These are usually the more difficult of the courses you will take for your degree. These classes can include calculus, physics (often times calc based), gen chem, organic chem, etc, Since they are prerequisites for most of the classes required for your major , one ends up taking these their first two years of college. The difficulty of these courses may be attributed to the actual rigor of the course itself, or the fact that it is not necessarily in a field the student feels passionate about and can therefore be difficult due to the lack of motivation, or a combination of both. Regardless of why theses classes are difficult isn’t really the point, the point is the early placement of these “difficult” courses in one’s college career. In my opinion, this is a major reason that makes science seem harder.

    Non-stem majors also have pre-requisite courses but they usually are courses within the major itself. As for the ones that aren’t, they tend to be a less rigorous alternative to those of the STEM majors such as college algebra instead of calc, maybe an intro bio/chem/physics course to meet gen ed requirements but these intro courses are no where near the level of gen bio/chem/phys. Majority of the rigor in these majors come from upper division classes taken in the last half of the college career. By then better study habits are developed and they no longer are perceived as difficult as they would have been if taken early on in their college career.

    Also another aspect of the difference in education formats is how we grade each major. Science majors, at least those of biology and chemistry, are typically graded on exams only. Whereas, non-STEM majors are graded based on their performance on various assignments; readings, papers, quizzes, exams, etc. Experiencing majors in both these areas I realized I spent much more time doing work for my non-STEM major but it was all assigned directly. Expectations were clear. Whereas, with my STEM major, majority of my work was learning how to study effectively and holding yourself accountable. Once you figure out how to study effectively for yourself, it is very easy, especially when you love your major. But trying to learn what works for you and how to motivate yourself to do something that you aren’t directly assigned can be very difficult.

    TL;DR. I believed STEM majors (excluding engineering) are perceived as more difficult because the student has more difficult courses initially in their college career before they develop effective study habits. Also STEM students tend to have less specific expectations of them which puts a lot more responsibility on the student to succeed within the major

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