> On the other hand, if you did not bother, a student might complain and have
> a point.
cover your ass, then. Why should you let random students decide how you grade things? If anyone, teachers need to be independent thinkers.

…
Even if it’s a small (less than 0.5), it seems to me that it may be worth it anyway. This is because there is little to lose by taking some attempt to normalize. On the other hand, if you did not bother, a student might complain and have a point.

All the courses I have taught or graded so far had at most 30 students, not enough statistics to see a clear bi- or even multi-modal distribution. But I do have seen excellent students that still stick out clearly from the good ones. And I have seen students who should have definitely revised their choice of subject…

When I taught my 300-student course last spring, we solved the TA problem by having a single TA teach all 6 sections (all in one day). We had graders to help him. No partial credit, so no ambiguity in grading.

Where we had a problem, that I never solved, is with our quizzes. The only way not to give the students in later sections an advantage was to make 6 different versions of each quiz, one for each section. This was a huge pain and in hindsight a dumb idea.

After wasting so much energy on making 6 equivalent yet different version of the same quiz each week, I was totally disinclined to run stats on the class to check for inequities due, for example, to the 1:00 pm section having 5 more hours to study than the 8:00 am section. Or for any cheating resulting from info about the quiz topics leaking from the early sections to the later ones.

You’re a saint in my view for taking the trouble to check for inequities and to adjust grades accordingly. Me? I’m way too harried by other responsibilities and just too lazy to give a damn.

Hmmmm…so, you want to measure the lumonosity of 300 objects, and you have uncalbrated visible light measurements made by a bunch of independent amateur (but skilled) astronmers. You then measure UV brightness for all the objects, and use that to callabrate the visible measurements. Legit? Seems so, unless there’s some systematic variance in the visible/UV ratio.

By analogy, this system rewards students with low homework/test ratios if there’s any correlation between that and section assignment. Would you think of that as a second order effect? One could make the argument the homework/test ratio measures ‘responsibility,’ which is as much a parameter of individual students as ‘intelligence.’

Interestingly, this should let you test hypothesises about one section being brighter than others…finaly answer that long-standing question if the brighter (or more responsible) students take the morning sections.

Robert–have you ever seen those multiple peaks in practice? When I TA’ed classes (in economics), I’d always predict that grades would have bimodal distributions, and I was always wrong!

Robert, do you believe in those five categories because we recognize five letter grades? Maybe there can be seven categories, like in Newton’s partition of the rainbow. Or perhaps only three, like in the Norse partition. That’s how Professor Jackson grades his advanced math classes: you were active in the class and knew your stuff, and get an A, or you weren’t all that active, were out of it for long periods, and didn’t seem like you knew too much, so you get a B, or you gave up halfway through, don’t know the material and get an F.

You are of course completely right about arithmetic means assuming affine structure. Naturally, assuming each of the assignments you wrote is of equal difficulty to a student who was first exposed to the material in your class, using the arithmetic mean to determine their score is the logical way to reward effort that leads to understanding. On the assumption that you get about the same kinds of students in each of your sections, normalizing sections is probably a good idea. Throwing away the outliers by using the median score to normalize sections is probably even better.

One thing I’m always interested in whenever normalizing grades comes up is, how do you avoid punishing the kids who take time out of their schedules to help other students? A simple normalization method (fitting scores to some kind of curve) would lower their scores by as much as it raises the scores of the people they help- making schooling pointlessly competitive. Students should be encouraged to present material to each other, because teaching is just about the best way to learn.

I strongly believe in the distinction along the lines of “excellent”, “very good”, “fair”, “just so” and “fail”. And everybody can tell an excellent student when one sees one. A “good” student is obviously better than a “just so” student. But that’s about what you can say about grades. Thus I think ideally the situation is as described in comment #7, each section has multi-peaked distributions and that tells you which grades the students get.

Already arithmetic averages of grades/scores are dodgy, it’s not clear that “very good” is really the middle of “excellent” and “fair”. I have heard people argue for example that one should compute geometric or harmonic averages but not very convincingly. Arithmetic averages requires an affine structure the others something else and usually this is not given. Julianne above argues that one should renormalise the points deducted rather than the ones given. This is already an appreation of this fact. But this is only good for good students. If somebody writes only very little on a problem you are typically giving points for what you find and do not deduct point for what’s missing.

Last week on the news I heard a report that some grades (was some business news, some costumer satisfaction measure) had improved since last year: In Germany grades are usually 1 to 6 with 1 being very good, 2 good, 3 satisfactory, 4 sufficient, 5 not sufficient and 6 complete fail. The report said that the average grade had improved from 2.5 to 2.0 . OK, they computed averages what ever those mean. But then some spokes person said that the improvement 2.5 to 2.0 was a “20% improvement” . I couldn’t believe my ears. How math illiterate can you be? What is 20% of a grade supposed to mean???

I am fearing, multiplying points (deducted or given) by a renormlisation constant is not much better. It only works in a small window of grades/points.

Ideally, your sections are large enough that you have sufficient statistics and you do a histogram in each section, identify the peaks and give grades accordingly.

Actually, the students who end up complaining about grading styles aren’t the most “dimwitted”, but the most opportunistic.

The ones you thought were “dimwitted” might be attempted opportunists who just can’t hack it. Or maybe they really wanted to learn but don’t have any talent. Maybe they’re in the wrong place for the wrong reason. Ultimately, you can’t save them, all you can do is try to teach them something and grade them based on whether or not they learned something or know the material… or whatever other criterion you’ve chosen. At any rate, they’re probably accepting whatever grade you give them, and going to their quiet place to sulk, and/or find something else to be interested in than your class.

It has been my experience that the students who talk about grading the most are the ones who get good grades for no reason. Getting a better than deserved grade is almost as bad for a person as getting a worse than deserved grade.

And I too hate the fixed-percentage curve. I work it by giving them a “minimum grade contract”. If they reach some percentage threshold, I guarantee them a given grade or better.

most teachers want to reward both knowledge and personal growth, so their already conflicted. the goal of an introductory science class is both to teach some results (the earth is round, it goes around the sun, a plot of Doppler shift against distance shows that things that are far away are moving away from us…) and to teach some philosophy of science (we build theories to explain facts and make predictions regarding future observations). some students will come to a class already knowing most of the material; perhaps they should have simply taken a test and been given credit for their knowledge, and then have taken a more interesting class? others may have come in not knowing anything but after studying carefully they could get the material, perhaps they deserve better grades than the kids who kinda know stuff from their engineering major roommate talking and are pretty sharp sometimes, but otherwise play halo on their xboxes all day? but talking about student archetypes isn’t really a good idea because the boundary conditions are so complicated that it’s hard to come up with all possible solutions that your arbitrary student will be a linear combination of.

ultimately, grading is a hard question, and while grading to optimize the number of students who end up joining your field may be a scientific question, most universities just want you to teach a completely random collection of students some tidbits from your field, which may conflict with your desire to both challenge and give an A to students who seem like they want to join your field (whence you might get profs like the dude who came up to me and shook my hand when i was hanging out with some physics majors discussing physics and physics homework in the physics lounge at my school… but when i identified as a math major told me ‘i dont tlk 2 math majors’).

i guess whats most interesting about the grading question is that almost every science teacher has a strong opinion on how&why. i wonder if they evaluate the grades that past teachers have given their new students based on their own criteria on how&why. when all you see on someone’s gradesheet is: B B+ A C, and it’s not annotated by ‘i think students should be graded on %criterion%’, how useful is that? what happens when you get a student who got a D because his professor refused to grade his homework when he answered the questions correctly, but found the answers using a technique that wasn’t gone over in class or in the book? also, higher level classes are often graded much easier than lower level classes, but not always, so you can’t count on that factor.

so. grading is hard, and the grades are then fairly meaningless. As a student, i just go to school just to try to learn something, because it’s easier to find things out when you have a teacha their to tell you stuff or ask questions of than just by reading books + wikipedia, and i don’t even care about my grades. another extreme position is that of some of my friends who are there to qualify for some other school and need A’s but don’t give a damn about what they’re studying.

and i’m going to be pretty depressed when some bureaucrat looks at someone else’s non-meaningful qualifications and selects them over me. because of the well-known cognitive bias favoring meaningless, easy to access information, whence we get processors designed for marketing like the pentium 4 and seagate falling in line with the rest of the industry in falsifying SMART checks to make their drives look good. or people buy sprite instead of their grocery store’s lemon-lime soda even because sprite is twice as expensive, and more expensive obviously means better; besides coke is a trusted name in soft drinks (if carl went to harvard, and carlos with to umass boston, obviously carl is the better student). and because of the need for bureaucrats to cover their asses and avoid doing things they may need to justify in the future (nobody ever got fired for buying ibm…).

so: grading is hard. grades are pretty meaningless and may even be harmful, unless you were wanting to reward grade-grubbers at the expense of serious students. maybe all classes should just be pass/fail on the grounds that either you learned enough to pass or you didn’t?

‘i am spartacus’ capitalization to let everybody know im an undergrad with a learning disability. in my case it’s asperger’s syndrome, and describing what that means is pretty tangential to this discussion of grades. i just want people, when they say that it isn’t and can’t be their goal to grade everyone perfectly, to know who they may be allowing to slip through the cracks. i understand its hard to give people the grades they deserve, but it’s also necessary in a way that i think that many professors aren’t really comfortable with assuming they think even think about it.

I think this is one of the best ideas I’ve seen for normalizing across TA sections. But what if the TA is teaching a lab, and some students find labs more engaging and do better there than on their exams?
There seems to me something fishy about having one their exams influence their section grades. They should be separate - yet I can’t find a cure for normalizing across TA sections.
The way they do it at my school is that 35% get A’s, 35% get B’s and the rest get the rest of the grades. I don’t like this at all, since I know more students deserve A’s.