# Why target for low grade medians and generous curves, rather than extra credit? [duplicate]

There seems to be a trend with science and math classes especially, where target distribution for the absolute grades are somewhere in mid Fs. But then the curve brings all the students with 30s and 40s into high Bs or even As.

What's the rationale here? Isn't it effectively the same as having assignment weights sum up to over 100% sans the stress aspect?

• Sorry, this isn't very understandable. And where do your assumptions come from about "trend" and such? Mar 2, 2023 at 17:56
• @ZeroTheHero - one advanced physics course I took was set up so that a grade in the 30's was in fact an A. The homework and tests were made so that any given problem was extremely difficult to actually finish fully and correctly. The point was for the professor to see just how far along you actually got. Different philosophy. An extremely good course all the same. Mar 2, 2023 at 19:22
• @ZeroTheHero - and yet it was one of the best classes I ever took. I learned a great deal about how to wrestle with difficult problems, which has served me very well over the years. Learning how to approach hard problems in the real world needs practice and training, not a bunch of problems with a neat, simple. "right" answers. Mar 2, 2023 at 19:52
• @ZeroTheHero No one has suggested an exam that is needlessly difficult with respect to passing. The situation described is one where the threshold for passing an exam is far lower than the maximum possible credit on the exam, rather than a more typical "90% for an 'A'", etc. Mar 3, 2023 at 0:06
• I don't think this is a duplicate of the associated question. That question is about whether curving is fair. This question is about why target a low average score on an exam. One can make 40 a B and 50 an A without curving. Mar 3, 2023 at 9:44

The conversion of numbers to grades is entirely arbitrary. For example, in England the norm is something like:

• 40-55 = C
• 55-70 = B
• 70-80 = A
• 80-85 = A++
• 90 = you should be teaching not me
• 95 = you should get a Nobel Prize or the equivalent
• 100 = I am repenting of all my sins because you must be the Second Coming

Learning flexibility as to conventions is an important life skill. Setting the scale as it is has some useful meaning to the instructor. (For me, 1 point on an exam = what a student who basically knows how to do this problem can do in 30 seconds.)

Also, doing different multiples can relinearize the scale in different ways. If you want to require that an A student gets twice as many points as a C student, you can't do it simply by multiplying all the points as extra credit.

• As an outsider to the English system: is this much exaggerated or are exams really created in a way that, say, 1 person in 20 years ever hat 95%? Mar 2, 2023 at 19:58
• @user111388 academia.stackexchange.com/q/191600/17254 Mar 2, 2023 at 20:16
• I got a 96 for one of my UK MSc courses. I'm sure my Nobel Prize must be in the mail =) Mar 3, 2023 at 1:17
• @user111388 it is a little exaggerated in the 85-100 range. But in my 8 years as faculty, I've only given one 90, and I'm quite a generous grader. I'd say that there is probably one 90 a year in our department (on a single assessment, usually coursework, not averaged over the year). Also worth noting that we don't use letter grades. So what this answer calls A+++ we call "1st class with distinction", A - 1st class honors, B encompases 2nd class honors (upper and lower), C encompasses 3rd class honours and pass without honors. Curving is also less common in the UK I believe. Mar 3, 2023 at 9:22
• @IanSudbery: Thank you, that's really interesting! So, is 100 different from "everything was answered correctly"? In other words, if you would immediately after you created an exam, solve it, would you obtain 100 points? Mar 3, 2023 at 21:26

You seem to assume that percentage of correct answers is independent of the questions asked.

Any experienced exam writer can manipulate the median / mean in a wide range. Sometimes, it is more important to give difficult questions and expect a good student to solve a quarter of them then to give easy questions and expect a good student to solve over 90% correctly.

You seem to be complaining more about the stress level caused by not being able to answer questions. That shows probably a lack of communication by the instructor in charge.

• @Layman - what's the difference? If everything is announced ahead of time, then you know what is going on. Mar 2, 2023 at 19:36
• @ZeroTheHero - Solving problems that are new to you (but based on what you should know) is an important life skill, and I want to test whether students have learned to do this. Problem solving in the context of a timed exam has a high failure rate. Mar 2, 2023 at 19:46
• @Layman - that doesn't work if you're expecting a C student to get 5 out of 20, a B student to get 10 out of 20, and an A student to get 15 out of 20. Mar 2, 2023 at 19:52
• @ZeroTheHero - I write an exam with 5 boring problems I expect most students to do, and I want the best students to also solve 1 interesting problem. I know 10 interesting problems and decide the best students might as well have a choice of which interesting problem to do, the choice of trying to make partial progress on 2 or 3 of them, and also the choice of skipping some boring problems and doing several interesting problems instead. Then the exam becomes one where the best reasonable grade is around 40% (the 5 boring problems plus 1 of the interesting problems, out of 15). Mar 2, 2023 at 21:25
• @ZeroTheHero How else are you interpreting "distribution in the mid Fs before curve", where people actually get As Bs and Cs? Clearly they are not actually Fs, they are actually the grades the students receive, whatever number is put on those letters. Mar 3, 2023 at 1:31