"99% of the time they're not a measure of ability, they're a measure of obedience, and your ability to persuade teachers."
This is false. Grades correlate reasonably well with ability. Plenty of people get good grades without corresponding ability, but 99% is a laughable exaggeration.
What would be evidence for that statement, in view of the parent comment to yours that disagrees with that conclusion? Where would one look for research on this issue?
suggested that grades correlate less well with ability (or any other meaningful characteristic of students) than supposed by the teachers who give grades to students. I'd love to hear about current research on this issue.
Seriously? Do you really believe that? Given a room of people do you honestly believe that in talking about, let's say Math, or Physics, or Chemistry that you couldn't immediately identify which of them had grades in the top 25th percentile versus the lower 25th percentile? I bet I could _even without having studied those domains_ in 20+ years.
Now, I'll agree that grades don't correlate _perfectly_ with ability for _everyone_ - we all know the bright slacker who doesn't turn in his homework, and maybe skips a test or two. But, in general, a student who score 95% in physics knows their material very well. A student who scores 15% in physics is probably clueless.
Math, Physics, and Chemistry are easy to objectively grade, so I'd accept that they tend to have higher grade quality (a notional metric of the correlation of grades to ability) than e.g. literature, drama, sociology, pottery, etc, where the grade quality correlates to the ability of the grader.
Physics classes don't prove a blanket statement regarding grade quality over all subjects, any more than Yao Ming proves that Chinese people tend to be seven feet tall, or the King of Sweden proves that Swedes tend to be kings.
Except that's not what I said. Too many people around here try to pretend that grades mean absolutely nothing. I doubt that nothing you did in school had any relation to the real world, and I pointed that out to you in the hope that you'd realize that the burden of proof in this argument rests on those who would try to argue that grades mean nothing. In the absence of actual data, which no one has provided, it doesn't make sense to give any merit to the anecdotal arguments of the minority rather than the equally anecdotal arguments of the majority.
With a range of classes from remedial, normal, advanced, and honors and a selection of electives I think most people's are intelligent enough to get a 4.0 in HS but few people can get there without significant drive. Compare that with a medical program where you really do need to be fairly intelligent, knowledgeable about your subject and willing to work your ass off to get a 4.0.
This is false. Grades correlate reasonably well with ability. Plenty of people get good grades without corresponding ability, but 99% is a laughable exaggeration.