In comments on my earlier post in which I mused on the wisdom of having chemistry and physics courses serve to weed out an excess of premed students, Peter R. wrote:

1) There would be far fewer chemistry professors (albeit happier) if pre-med students did not take chemistry. Chemistry majors are always, and have always been, the minority of students in general and organic chemistry.

2) The idea that chemistry is a “weed-out” course is misleading, because it is not the chemistry instructor’s job to choose who goes to medical school. Our job is to determine how well our students learn chemistry. It was not the chemistry faculty that made chemistry a requirement, although they certainly benefit from it. The students “weed” themselves out.

These are observations worth discussing, not least because I think discussing them will help us become more aware of some of our assumptions about how colleges and universities ought to work.

Let's start with the second observation first -- that chemistry professors are really only charged with evaluating student performance in the context of the course requirements for the particular chemistry course they're teaching.

I agree that this is what the job description is. You teach the class, you assess the students (with problem sets, exams, lab reports, and the like), and you assign the appropriate grade. As I've discussed before, there are differing philosophies on what it means to assign the appropriate grade -- whether the grade is supposed to reflect something like the student's distance from the Platonic form of "getting" the material, or whether instead it should reflect how many standard deviations the student has scored from the mean for the class, whether that mean is relatively high or relatively low on an absolute scale. But your garden variety chemistry professor shouldn't also be tasked with determining which students are likely to succeed in medical school or to make good physicians* because your garden variety chemistry professor have very little basis for making that determination, having never been a physician or even a medical student.

However, there are a couple of things that complicate this picture.

One is that I cannot help but feel that some chemistry professors end up adopting the grading-on-a-strict-bell-curve model because of the relatively large number of premeds compared to chemistry majors enrolled in the classes they teach. The assumption is that the chemistry majors will make up most of the As and Bs on that curve, while the teeming masses of premeds will make up most of the Cs, Ds, and Fs. (Premeds who end up making As are sometimes actively recruited to consider majoring in chemistry and perhaps even pursuing graduate studies in chemistry rather than medicine>0

This in itself wouldn't necessarily be worrisome -- maybe it would just be a reasonable prediction about the range of competency and motivation in the student population. But sometimes the prediction that premeds won't learn organic chemistry (for example) as well as the chemistry majors seems to manifest itself in a pedagogy that puts less onus on the professor to teach the material and more onus on the students to learn it their own selves.

At which point, the professor in question is pretty much only determining how well the student learn chemistry, but not doing the teaching that you might have assumed was part of the job.

On the other hand, however, I think it's an open question how medical schools would respond if chemistry professors suddenly got very serious about teaching all of their students -- premeds included -- in such a way that the vast majority of them learned the course material, and learned it very well. The anecdotal reports I heard (while I was teaching in an MCAT preparation course to help pay the bills between graduate) suggested that a school where more premed students were getting As and Bs in chemistry was judged "easier" by medical school admission committees, while one where fewer premed students got As and Bs in chemistry was judged "more challenging". If that's true, that would seem to penalize students with professors who take pedagogy more seriously than the bell curve.

And that makes it seem an awful lot like medical school admission really are pushing the weeding out onto chemistry professors.

Myself, I think that the ability to master the basics of general chemistry, or organic chemistry, or physical chemistry, is not the sort of thing that is (or ought to be) perfectly congruent with one's major.** If taught well, the underlying principles of chemistry ought to be intelligible to almost any intelligent person (or at least, to more than not). Assuming up front that a whole class of students one is teaching are constitutionally unable to learn the material is giving up at the very start. And regardless of the instrumental use that medical schools might get out of this stance, I think it rather undermines one's teaching duty to one's home department.

Now, onto the first observation, that there would be fewer chemistry professors if chemistry classes (whether "weeders" or not) were not required for admission to medical school.***

The situation is such that chemistry departments often exist to offer "service courses" to support pre-professional programs. In many universities (including my own), philosophy departments also justify their existence by their service courses (in our case, the large number of courses we offer that fulfill various general education requirements). It's nice to be able to point to a curriculum that needs to be taught, not just by the lights of your own discipline (which, obviously, thinks that core material within that discipline is terribly important), but also by the lights of other disciplines -- especially if those disciplines have multitudes of customers students. This kind of demand means that, when you get the staffing to teach the coursework that is being demanded, you also get colleagues who are doing interesting research, who can add breadth to the courses you offer to your majors, and with whom it is productive (and fun) for you to interact.

But, especially in science departments, and especially at research-focused universities, this increased population of professors also leads to an increased demand for research funding, equipment, and lab space, and an increased demand for graduate students and technicians to keep the professors' research projects moving forward. (Those graduate students are also in demand to do the grading in all those well-populated premed courses.)

Down the road, of course, this will mean more people with Ph.D.s competing for those professorial posts**** (which only exist in the numbers they do on account of the demand generated premeds required to take the courses those departments' professors teach) competing for the posts there are.

This is not a huge incentive for chemistry professors (or chemistry graduate students) to question the common wisdom that general chemistry and organic chemistry (and maybe even biochemistry and physical chemistry) are absolutely essential preparation for medical school.

Perversely, the supply and demand equation also seems to act against reexamining the quality of the teaching in those required premed chemistry courses. After all, if you turn out premeds who are too smart, what are the chances that the senior faculty will die off at a reasonable rate and open up some jobs for the Ph.D. chemists they've trained?

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*Despite this, I will confess that the slogan "Save a life: fail a premed!" gained a certain traction with the chemistry TAs in my graduate program.

**If I didn't already think that majors and the subjects that one is good at were separable, my friend the fine arts major who took math courses for fun would have pushed me in that direction.

***The claim that these chemistry professors would be happier depends, I think, on the current state of the transaction between premeds and chemistry professors, in which the students only care instrumentally for what the professors are offering and the professors have already decided that most of those premeds won't be able to learn the material, or that they are diluting the contact between chemistry professors and chemistry majors, or what have you. I'm not saying that the claim is false, but like most counterfactual claims, how we evaluate it depends a lot on our hunches about what other moving parts in the situation might have relevant effects.

****And before that, for postdoctoral appointments.