Monday, November 07, 2011

 

Grading and Choosing

You know that feeling when you’ve suspected something for a long time but couldn’t prove it, and then someone proves it for you?

This article had that effect. It’s about how student attrition in STEM majors is actually higher in more selective institutions than in less selective ones. It brought back vivid memories of my days at Snooty Liberal Arts College, and even of late high school.

The article is based on a study by the College Board that suggests that grading is substantially harder in STEM majors than in most others, so students who don’t immediately hit it out of the park in STEM classes tend to gravitate towards the more-welcoming liberal arts and business classes. But that tends to be less true at less selective colleges, oddly enough.

I like it a lot because it explains a number of disconnected impressions I’ve picked up over the years. For example, in my student days, I recall noticing that even though the STEM classes (we didn’t use that term then, but still...) were “harder,” they also had much flatter grade distributions. It was easier to pass a history class than a chemistry class, but easier to get an A in chemistry than in history. The history classes had bell-ish curves; the STEM classes had flat lines. They were easier to fail and easier to ace; the “squishier” subjects were the land of B’s and C’s. Even in my wheelhouse, I was the master of the A-minus; full A’s were basically unicorns. In physics and chemistry, the top students finished with GPA’s above 4.

So saying one is “easier” is kind of misleading. It’s easier to pass, yes, but harder to really nail.

(One underappreciated variable, I think, is the level of consensus in the field. As far as I know, there’s remarkably little controversy in the scientific community -- I’m open to correction on this -- about the material that gets taught in the first couple years of the undergraduate major. That’s certainly not true in the humanities and social sciences. When consensus is missing, it’s harder to definitively nail a subject.)

Students noticed. Those who didn’t much care what their degree was in, as long as it had the SLAC name on it, clustered into English or history. (SLAC didn’t have a business major.) Those who cared strongly about their own “squishy” specialties had the mixed blessing of a bunch of classmates who had taken the courses as second choices. The idea -- accepted as gospel by all -- was that you were either a science person or you were not. If you were, you stuck with it and did great; if you weren’t, you did something else.

(This was made explicit in Organic Chemistry, which was pitched unapologetically as the pre-med weedout course. Difficulty wasn’t a bug; it was a feature. The idea was to winnow the herd, and to leave only the truly worthy still standing.)

In the cc world as I’ve experienced it, that assumption isn’t widely held. Here the idea is that the community (broadly defined) needs more STEM majors, and it’s our job to make that possible. Rather than weeding out, the goal is to bring people in.

If you start with that assumption, then of course your approach will change.

It isn’t just about easier grading. It’s about the purpose of a given class, and therefore the approach to it.

If I were appointed guru of American higher ed, one of the edicts I would issue would be that theory should be taught inductively. It rarely is, which, I’m convinced, is why so many undergrads spit the bit. (This is probably why I bombed geometry, but never mind that.)

Theory is easiest to learn when there’s a context for it. When you know why you need to know something, you’re much more likely to get it. That’s partly a function of motivation, but it’s also a trick of memory. A theorem derived on a board by someone with his back to you is far less memorable than something that comes with the force of “eureka!,” solving a problem with which you’re engaged.

At its base, I suspect, theory is based on pattern recognition. And pattern recognition is easiest when you’ve seen a whole bunch of examples. If you can get a student to the point at which a theory comes as a solution, rather than as an edict, you’ve won. And if you can get students to test theories against each other, you’re raising the cognitive level of what they’re doing and engaging them much more fully.

Instead, science is too often taught from theory to application. Worse, in the selective settings, it’s taught with a clear goal of thinning the herd. At least at the community college level, we don’t consider ourselves to have failed if a significant portion of a chemistry class does well. At this level, we actually pay attention to the teaching itself. That’s not to deny that there’s much more work to be done -- no argument there -- but at least we’re attacking the right problem. The goal shouldn’t be to keep science pure by keeping the great unwashed out of the lab; it should be to keep science accessible by forcing it to be true to its radically democratic roots. Data are no respecters of rank.

If we’d like to direct more of our bright young minds into STEM fields -- a goal I find absolutely worthy -- the elites may actually have something to learn from the community colleges. Hey, Harvard: you’re welcome.



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