Saturday, May 09, 2015

Grading on a Curve

I was chatting with a HS student the other day, and they told me that they'd been learning about normal curves in math, and the math teacher had told them to be prepared because in college their work would be graded on a curve.  The student was really worried about the idea of being graded on a curve, so they asked me if I grade on a curve.

I don't.  I doubt many humanities types do.

And, to be honest, I think there's been a change in approach, and not many of my colleagues at NWU do, not in the sciences, social sciences, or business areas grade on a curve, either.

I'm pretty sure folks at super elite schools never graded on a curve in the sciences.  Maybe I'm wrong, but I can't imagine chem profs at Harvard thinking that half their students should get Cs or below, not in recent history, anyway.

When I was an undergrad, my big science and math sorts of courses were graded on a curve, or at least we were told they were.  I remember a chem test where the median score was 86/100, and that was a C.  And I was terrified and horrified.

The attitude at my undergrad school (a then smallish public R1 known for ag/science) seemed to be that first and second year chem, calc, physics, and bio type courses were "weeders," and were supposed to make students who weren't going to get into vet or med school rethink their career goals earlier rather than later, and change majors to something else.

And that's one place where I think professorial attitudes have changed.  I think now, my science colleagues think that it's their job to help their students succeed rather than to weed them out.  The courses are still tough, and students fail, but my colleagues don't talk about weeding students, but rather figuring out how to help students.

The other place I'd say attitudes are different here (but I don't know if they've changed), is that we worry a whole lot about retention and graduation rates.  Did my undergrad institution worry about retention back then?  I don't know.  But we do here.

We do lose students who decide they aren't getting into our nursing program, especially, since we can serve way fewer students than wish to be nursing majors; they go elsewhere to study nursing, often.  (If we could afford to hire more nursing faculty, we could easily double the major with no real difference in student quality; the entry is that tough.)

What about you?  Do you folks grade on a curve? 

What are attitudes at your school about grading on a curve?


  1. Here at Georgia Tech, my students tell me their grades are sometimes curved in the math/sciences/engineering, but only in the student's favor. You get a 60/100 on a Physics exam, but you might still get a C or a B because no-one in the class got above a 75.

    1. That makes a lot of sense, Sapience! Thanks for the feedback.

  2. Oh, there was definitely a curve in the sciences at Yale in the 1990s--and I presume today, too. Half the people I knew started out pre-med and most didn't last a semester.

    But like Sapience, I've always understood the expression "grading on a curve" to mean grading generously: if the class is hard, the person who sets the curve makes their top score the new 100. I sometimes curve exams (never essays), if the distribution seems off or I think I inadvertently made it harder than it should have been.

  3. I curve in science classes. (Sometimes hugely - I used a transformation once when the mean was below a 50, where you take the square root of the grade and then multiply by 10. Someone really low gets curved a lot, but if someone gets a 90 they don't suddenly get more than 100%.) Always up, if my exam means are lower than my normal (e.g., all of a sudden a section gets an average of a 69 instead of a 78). You can also calculate means, standard deviations, and z-scores so you can get a statistical/scientific basis for your curve.

  4. I don't grade on a curve, but whenever I was subject to a curve, it was always to raise people's grades, rather than lower them.

    Some of my students in Humanities have begged for a curve. It is always disappointing to them when we say no.

  5. I got out of the sciences (in the mid- '80s, at a place pretty similar to Yale) because I didn't want to fight for tenths of points with pre-meds. It took all the joy out of learning about stuff in which I was genuinely interested. So yes, I guess there was still a curve in the sciences there then. Whether there still is now, I'm not sure. There wasn't in the humanities (and presumably still isn't, given all the debates about whether >50% of the members of a class should be getting As. Coming from a not-too-selective high school which was nevertheless academically rigorous enough to make an A hard to get, I was probably a bit naive about what the B+s I often got meant. Fortunately -- or unfortunately, depending on whether you consider getting a Ph.D. a wise choice -- I wrote a prize-winning thesis, which propelled me into grad school).

    I only curve when the grades are disastrously low (e.g. when I try giving multiple-choice tests, even ones I think are easy, in large gen ed lit classes), or for class participation (I assign points to presence, contributions, and various prep activities, add up all the points, set the median, usually at a B, and work from there. I do, however, reserve the right to exercise discretion in setting the top and bottom as well -- so, if a class was really uncooperative/lazy, nobody may get an A in participation, and if all members were generally cooperative/hard working, the minimum participation grade may be a B- or C+ rather than a C or D or F).

    As far as I'm concerned, curving is one method for performing a reality check on my expectations (while reserving the right to insist on certain minimum standards, even if students resist meeting them).

  6. I don't grade on a formal curve, but I do some informal clustering / scaling of grades on exams, which are the only things that get number grades: spread them out from highest to lowest, and see what the spread looks like and where the gaps are. Usually, they fall into distinct clusters with logical cutoff points, so I'll call the first cluster the A range, the second one the B range, and so on.

  7. I don't curve at all. Sometimes classes do great as a group, and sometimes there are some folks who don't do great.

    I've never been a place where the curve hurt instead of just helping.

  8. I look at the distributions. If the class average on a quiz or midterm is somewhere in the thirties or fifties, something went wrong. My job is to figure out what and determine the best response. Occasionally that means that I'll bump up the marks overall or offer an extra credit opportunity. I've never pulled a class down for exceeding expectations because I'm grading against the standards, not for a certain distribution of marks!

  9. saucyturtles5:06 PM

    I've done a little curve in the students' favor, but not all the time. On changing expectations, my grandfather, who taught at NYU from 1929 - ~70, said during the depression and the war, they were urged not to give so many low grades so as not to lose students. Then during the baby boom years, they were urged not to give so many high grades for the opposite reason. So weed-em-out has come and gone and come and gone again over the years.

    1. Saucyturtles, the back and forth makes so much sense. I was at the end of the baby boom, so they were weeding, I guess. But now they wouldn't be because there are fewer students graduating from HSs. Thanks!