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Well, this seems like one of those social problems where a technical solution might be available. 1) Figure out the number of students taking course n. 2) For

by scarmig 14y ago

Well, this seems like one of those social problems where a technical solution might be available. 1) Figure out the number of students taking course n. 2) For the first assignment, figure out the number of questions m you want. 3) Make a question bank of size M. 4) Satisfy the constraint n < (M-m)! 5) You now can uniquely identify uploaders via the set of answers they upload. If you're willing to kick people out of the class and mark them as cheaters, you can now do so without worrying they're trying to frame someone else. This can be refined--maybe make it so that the question bank is large enough that several people conspiring will be unable to randomly generate a sequence of questions that's been given to a real person, so they can't randomly screw people for shits and giggles. You could also make the questions differently phrased, making it harder to Google them. Depending on how many cheaters there are, you can also just make a question bank that's large enough that any given question is unlikely to have been uploaded by a cheater, though that rapidly blows up the size of the necessary question pool if you do have a significant proportion of cheaters.

michaelt 14y ago
The problem with question banks, at least in normal academia, is making sure everyone gets a question set of equal difficulty. If one person gets asked for an algorithm to find the length of a linked list and another gets asked for an algorithm to remove a node from an AVL tree, that's not fair on the second person. You could experimentally calibrate the question bank, seeing which questions trip students up the most, but that requires asking the same questions a bunch of times to different students, which is exactly what using the question bank was supposed to avoid! And if you want to reuse the calibrated data every year, you'll have to ask the same questions every year, which we prefer to avoid. I suppose with a sufficiently large student population an effective calibration might be possible - maybe Coursera will be the ones to do it!

by scarmig 14y ago

michaelt 14y ago

The problem with question banks, at least in normal academia, is making sure everyone gets a question set of equal difficulty. If one person gets asked for an algorithm to find the length of a linked list and another gets asked for an algorithm to remove a node from an AVL tree, that's not fair on the second person. You could experimentally calibrate the question bank, seeing which questions trip students up the most, but that requires asking the same questions a bunch of times to different students, which is exactly what using the question bank was supposed to avoid! And if you want to reuse the calibrated data every year, you'll have to ask the same questions every year, which we prefer to avoid. I suppose with a sufficiently large student population an effective calibration might be possible - maybe Coursera will be the ones to do it!