Submitted by mysteriouslime t3_z4gpi8 in explainlikeimfive
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GESNodoon t1_ixqt7ml wrote
Grading on the curve addresses the outliers generally. If the average grade is 68 but someone scored 100 (or a 0), you can ignore the 100 score as an outlier. You could have someone who is just really knowledgeable on the subject matter or someone who is cheating, which grading on the curve can be useful for finding.
kinyutaka t1_ixqwmho wrote
That all depends on the teacher. Grading on the curve doesn't really employ any complex math. It is just suggesting that they push the pass/fail line up or down based on what the teacher thinks it should be set at.
GESNodoon t1_ixqx2s0 wrote
Most that I have had that grade on a curve are setting x% as an "A", "B", C" and so on. Oddly this is how my employer does raises. A certain percentage of each department is going to get an "Exceeds" a certain percentage is going to get an "Improvement Needed" each evaluation cycle.
mysteriouslime OP t1_ixqvljq wrote
ahhh the bellcurve makes sense! i think i was imagining it as just a regular upswing curve, but that clears it up for me a lot - thank you!
ZLVe96 t1_ixqvrwb wrote
Real curves adjust the grades to fit the mathematic bell curve standard distribution.
Most teachers "curve" just by adding points so that the highest score is a 100. If the class takes a test, highest score is a 97, the curve is 3 points added to everyone's scores.
RigusOctavian t1_ixqx8ge wrote
To add to this, if there is one question that almost everyone got wrong, that can get thrown out too.
eloel- t1_ixqq3k3 wrote
Grading on a curve means setting the most mediocre student to a certain letter grade, say C, and scaling everyone up or down based on that. Means the class will have some fails, some As, and mostly Bs C's and D's
Contrast that with hard number limits (Below 50 fails or above 90 is A), which might mean the entire class could get As or Fs based on the exam difficulty and how the class does.
The first one assumes the class is somewhat normally distributed as far as knowledge on that topic. The second one assumes the teachers are infallible and create the exams at the same difficulty every time. Neither of these hold all the time, so neither method is necessarily better.
mysteriouslime OP t1_ixqq7t9 wrote
Okay I think I understand now! Thank you :)
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kinyutaka t1_ixqqqu6 wrote
Theoretically, in any group of people, the majority of the body will be average in knowledge and intelligence, and few will be outlying to the top or bottom. This creates a "bell curve", a hump in the graphical representation of the class.
If everything is done right, then the majority of students will receive a similar grade, hopefully around 70 (passing) anyway.
But if the concepts are harder, the whole class might get dragged back, putting the average grade lower, let's say 68, failing if you just grade the tests.
Grading on the curve corrects for the fact that they are doing the best they can, pushing the passing score down to 67. It allows for a teacher to fudge the numbers and allow for fewer failures for little mistakes.
But if you have a student that greatly excels in the test, that throws off the Curve. Among other things, it suggests that the subject matter wasn't all that hard and the "barely failing" students simply failed to learn the lesson.