<p>I'm fairly new to the reasons behind this practice, but I've heard enough horror stories, for example: well, the professor might give you a C despite your 95% in the class, because of the class curve. Also, the grade you get may also depend on how the prof is feeling at the time. Anyway, why can't the teachers just simply give out the grade you deserve, like "o, well you finished with a 86, here's your B, or here's your C" ??? Does the prof. gather all the grades and place them on a standard normal curve, thereby figuring out your z-score and all that crap ? I mean, this is going to sound really stupid, but what's the point of this process ? Anyway, is this true of all courses, or mainly difficult ones (math/science) ??? <---well, depending on what you think is hard, that is.</p>
<p>most profs at Cornell make up new exams every single time, so this can lead to some inconsistencies, same thing goes if the curriculum is changed. By always having the mean be a C or B-, the ones who perform best will always be rewarded with the best grades in the class, and the lazy ones wont benefit from just an easy test. It is also good if there is more than one section for a big intro class (like bio101) ... it makes it so you wont be screwed out of a good grade by getting a different teacher. At Cornell, different teachers teaching the same class must have the same grade distribution.</p>
<p>Another Cornellian speaking here.</p>
<p>The curve is a very good thing, trust me. It doesn't make much sense until you take the courses.</p>
<p>I "think" I understand the logic behind grading on a curve, but doesn't it negate the whole idea of what information/knowledge was successfully absorbed? At the extreme, 90-100% retention would still result in a curve that would place the 90's at the bottom. The opposite extreme would put the top of 0-10% retention test-takers at the top of the curve. I know these examples are ridiculous, but in real life it doesn't appear equitable that a student with a raw score of say 80% can actually fail a test. Thoughts??? In the real world, does a human element ("common sense") overrule the mathematics of a curve? Thanks.
PS Can someone explain how AP grading is calculated?</p>
<p>It usually works for large classes, and mostly involve shifting the mean to fit the desired letter grade (sometimes, meddling with the variance can be necessary). So it's quite unlikely that one will get C despite a 95% grade. But it's not impossible that some profs might use some arcane formulae or forceful fitting of the order statistics (grades often consist of mixtures of 2 or sometimes 3 normal distributions, and some people insist on forcing that single bell shape). The reasoning is just as gomestar explain: the grade distribution for one class should be the roughly the same over time and between different profs.</p>
<p>EDIT: This is not a response to BigDaddy3's post</p>
<p>On an exam with a high of 84, a low of 2, mean 63, median 68, and standard deviation 18, the curve is the ONLY way to ensure fairness. This is a typical set of numbers I encountered last year in my Math courses.</p>
<p>Consider what would happen if we didn't curve.</p>
<p>You may say, "why not just make the test easier?" But that's not the point. In the real world, it doesn't matter how much you know, just how much you know relative to everyone else. Einstein wasn't considered intelligent because he made a score on an IQ test. He was intelligent because he was more intelligent that nearly everyone else.</p>
<p>Consider if the test were easier. 100 people take an exam. 15 score 100%. The low is a 58. The mean is an 85, the median is an 87. This is also a decent score distribution. But the 15 people who scored 100% are NOT EQUAL. You need to challenge them to beat a curve, or they're going to be content acing easy exams without studying and won't really learn anything.</p>
<p>Yes I think the curve is fair, no I don't always get above the mean, but when I come out of my exam thinking I got a 36%, I don't have to worry, because the curve will take care of me.</p>
<p>I used to be a TA. In my experience, when a course is graded on a curve, professors deliberately make the exams difficult to avoid having to deal with a lot of student complaints.</p>
<p>No student ever complains if the curve turns his 78% into an A. On the other hand, can you imagine what would happen if a 95% turns out to be a C? Professors and TAs are human beings. They don't want to have to deal with that sort of thing.</p>
<p>If a 95% is so mediocre among the class that it's considered a C, they seriously need to make the tests harder. That's just ridiculous. When I think of "brutal curves", I think of the physics test I took freshman year where class average was marked as a D because the professor was irritated that the class didn't do better.</p>
<p>Undergrad courses, in my experience, are graded tougher than grad courses because the grads have to keep a B average to stay in school and the undergrads just need a C average. I know plenty of people at my school who pad their GPAs by taking grad classes. Ironic.</p>
<p>if you have a test on factual, "objective information", and all test takers have grasped the facts/knowledge (the teacher has done a great job, as have the students), why shouldn't all earn a high grade? Isn't the purpose to "educate"? Conversely, if all do poorly (lack of study and/or poor teaching), why should a segment of these underperformers receive an above average grade?</p>
<p>That's why we have program quality assessments.</p>
<p>The top students coming out of a qualitatively poor program at qualitatively poor school don't usually get the job over top students coming out of a superior program at a superior school. It's a "best of the worst," "worst of the best," "best of the best," "worst of the worst" sort of thinking.</p>
<p>Basically what I'm saying is, nobody is equal. You need a basis on which to evaluate people, and a curve does that most fairly of any system available.</p>
<p>There's no way that, at least in engineering classes (my area of experience), everyone will get an 80+. Averages tend to be around the 50-75% mark, with some brutal exams being lower, and first midterms in intro classes being easier.</p>
<p>Yes, theoretically, everyone might get a 90-100%. If that was the case, however, the professor might give out a ton of A's. There's no fair way of saying that a passing grade is a 93; you can easily go down to this level from a minor math mistake.</p>
<p>While a curve insures to a certain degree fairness among different teachers, etc., wouldn't it also put in an additional element of luck in that it depends on how good the people in your class are, and not necessarily how well the whole grade did. So while you remove one source of bias, you introduce another.</p>
<p>"if you have a test on factual, "objective information", and all test takers have grasped the facts/knowledge (the teacher has done a great job, as have the students), why shouldn't all earn a high grade? Isn't the purpose to "educate"?"</p>
<p>What the mean equals to in terms of GPA is not some exact number. Some department may give a range in which it has to fall, but the professor can pick either the upper or lower part of that range. I don't think the range cannot be changed, as a professor may petition for it to be raised if he or she feels like this year's class was outstanding.</p>
<p>Also, in college you educate youself. The professors does not educate you - you do that to yourself. In theory, you'd want to top the curve and therefore will go to extreme lengths to teach the information to yourself. The professor only guides the class: comes up with overall topics to study and supplements the textbook taking some material out and contributing other material deemed more important. Also answers your questions. But professor does not educate you really. He stands there 3 hours each week and talks about material. Then you go and spend 2-3 times as much time studying on your own.</p>
<p>The downside is that professors feel it is fine if the class has an average of 50-70%, meaning that students absorbed a bit over half the information presented. They cannot make exams that are way too difficult and go beyond the course material, so they either make the course go at a high pace and/or give little time for exams. Needless to say, if the course goes at a high pace, people come out with a huge mess in their heads, which is very common. If there is little time for the exams, it is the faster writers and thinkers who win over. Usually you think faster if you just memorize material. If you spend time figuring it out, you won't complete the other questions. But for some reason the idea is that by setting stringent time limits you will isolate those who know the material by heart. Although I think there was some study where it was shown that with limited time, the smarter students do worse than would be expected of them.</p>
<p>
[quote]
if you have a test on factual, "objective information", and all test takers have grasped the facts/knowledge (the teacher has done a great job, as have the students), why shouldn't all earn a high grade?
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</p>
<p>Ah, but how many college tests do you think are on simple facts? For example, I'll look at the biochem class I took last term (which was not curved but had a very generous scale - a 47% was a C). Was there factual knowledge in this class? Well, yeah, it's a science class. In the first half of the class it was stuff like formulas for enyzme kinetics, or the process of protein synthesis. In the second half of the classs, it was pathways, pathways, and pathways...and some molecular formulas. Was that what the tests tested? Heck no. The tests even allowed you to make cheat sheets with that material on it, so you didn't have to memorize it (though it could help you do the problem faster). A typical test question was something like "Write out a series of reactions to produce $SUBSTANCE from $OTHER<em>SUBSTANCE in a system which is unable to produce $INTERMEDIATE. Include all catalysts, intermediates, molecular formulas, and reaction mechanisms. How many mmols of $SUBSTANCE will be produced if you start with 3 mmols of $OTHER</em>SUBSTANCE?" Inevitably, the fact that the system was unable to produce $INTERMEDIATE made the problem about twice as difficult.</p>
<p>Generally there were four or five such questions for a 90 minute test.</p>
<p>Now, do you think that the whole class is going to get a "high" grade on something like that? Like I said, you only needed a 47% to get a C - and even then, close to 10% of the class got lower than a C, and another 10% dropped it. And this is MIT. People are smart. Of course, the professor could have written us much easier and more memorization-based tests, but how does that test our understanding of introductory biochem?</p>
<p>I agree with karthikkito, most tests I've taken in sci/eng classes have a class ave somewhere from 50-75%, and class ave is marked as something in the B-C range. It makes a lot more sense for the profs to write hard tests because it allows for more separation of scores instead of everyone being clumped together.</p>
<p>...and I realize that I might have misinterpreted BigDaddy3's question, and he might have been asking why shouldn't everyone get a high letter grade (or a low letter grade, as the case may be), rather than why shouldn't everyone be able to get a high numerical score.</p>
<p>Well, as for why everyone shouldn't get a low letter grade, that's pretty easy. Probably the prof wrote really hard tests. Or maybe the prof is a poor lecturer. Or both. In either case, why should the class' top-performing students get shafted?</p>
<p>As for why everyone shouldn't get a high letter grade...well, it depends on what a high letter grade means at your institution. To paraphrase the official standards of mine...</p>
<p>A = Student pwns the class material, can solve difficult problems in this area, can apply the material with no problem, and can readily extend just about any of it to all sorts of more complicated problems.</p>
<p>B = Student understands the material very well and can solve complex problems with it and apply and extend it.</p>
<p>C = Student understands the material well enough to solve problems in this area and move on to classes which require a working knowledge of the material as a prerequisite.</p>
<p>D = Student understands at least some of the material but probably has a significant gap(s) in their understanding, and may or may not be ready to move on to classes which require a working knowledge of the material as a prerequisite.</p>
<p>F = Student does not understand the material, is not ready to move on, and receives no credit.</p>
<p>So if you're a prof, working with these standards, you want to look at how the class did and figure out what are appropriate letter grade cutoffs to conform to these standards. A common shortcut/formula for this is to use a curve of some sort.</p>
<p>I've seen some pretty weird grade distributions. For my cellular neurobiology midterm last term, scores ranged from 10-92 (out of 100), class ave was 66, and scores were trimodal, with peaks at about 55, about 65, and the 80-85 range. I think the eventual grade cutoffs were something like 82 = A, 60 = B, 45 = C, with about 30% of the class getting an A on that test and about 15% getting below a C.</p>
<p>Do professors normally release all this detailed grade information..?</p>
<p>Yes. After every assignment and exam in curved classes, I got the mean, median, high, and standard deviation. Sometimes you also get a graph showing the score distribution.</p>
<p>If a course is curved to a B-, then one standard deviation above is an A-, and one standard deviation below is a B-.</p>
<p>You might want to read or see the picture at:
<a href="http://en.wikipedia.org/wiki/Bell_curve_grading%5B/url%5D">http://en.wikipedia.org/wiki/Bell_curve_grading</a></p>
<p>If the center of the curve represents a B, then 84.1% of the students will get a C or higher. If you curve to B-, then 84.1% will get a C- or higher. For reference, at Cornell, my first couple math courses are curved to a B-, and you need to retake lower than a C-. The curves and requirements are different in other courses.</p>
<p>The curve is a good thing. For example, my intro physics class had 173 students in it. The class average was a D. The professor, instead of reconsidering that maybe his class was kicking everyone's butt (and not for lack of effort, that class took me at least 20 hours a week of studying, and I pulled a C), just devised this complicated formula for grades that basically went in a circle and gave you the same grade you would have had if he just used your average. So, half the class failed. This reflects well on no one.</p>
<p>Meanwhile, my chemistry class was curved. No one had a perfect A, so the highest grade was made an A, and everyone else was scaled accordingly. This grades the class against each other and helps even out a large class. It also makes it easier to try to learn, because you know if you work really hard and still tank some, you know you won't be punished as much for trying as you would be in a class without a curve. These are obviously more beneficial in really difficult classes. </p>
<p>I'm all about the curve, I just wish it was easier to understand. Some professors turn it into rocket science.</p>
<p>Lauren, what if you're taking a course on rocket science?</p>
<p>Anyway, it should be mentioned that curving works best for large classes (50+ students, the larger the better it works) because for small classes, it is possible for a professor to actually evaluate each student and understand if they're each performing exceptionally.</p>
<p>mercury: I'm curious to how thoes 15 people that scored 100% on their tests would get different grades. assuming a 100% is the max you can get on the test, how would your 100% become a different score using a curve? a 100% means you got everything, so even in a curve wouldn't you still come out on top?</p>