Insufficiently Random

The lonely musings of a loosely connected software developer.

Friday, November 11, 2005

Randomly Grading Problems

So the class I was complaining about last week? The instructor typically assigns homeworks with 6 problems in them. We are to turn in solutions to all 6. The instructor then "randomly" selects 3 and uses those 3 to determine your grade. From what I can tell of the 6 problems all are equally worthy questions related to the course material, so its not like 3 questions are more accurate tools to judge student ability than the other 3 are.

With 6 questions per homework and 5 homeworks in the semester each question is worth 1.16% of my final grade. Remember that since this class is essentially pass/fail with 93% and below considered failing, 1.16% of my final grade is really worth 19.3% of the pass/fail grade. So each homework question is worth 19.3% of whether or not I am a good enough student to work on a PhD in Computer Science.

Remember that questions are randomly selected on the homework. So if I get 5 out of 6 completely correct and the one I got wrong is one of the ones graded, I lose 19.3% of my pass/fail grade. If another student gets only 3 out of 6 completely correct, but was lucky enough to have gotten all 3 of the graded questions right, they lose none of their pass/fail grade.

How exactly is this a fair judgment of the student's ability? For starters we have no idea if the other student (who only got 3 of 6 correct) really did get 3 of 6 correct or got 6 of 6 correct, as 3 of the questions weren't even graded. Secondly we're talking about 1 question being worth 19.3% of the pass/fail grade. If both students scored the same on all other homeworks and exams and both are close to the 94% pass/fail line, it is possible for the one student who got 2 more questions right on a homework assignment to actually fail the class, while another student who got those questions wrong will pass the class without a problem.

The instructor is grading this way to "save work for the TA". Other graduate courses on the same material at other schools require the students to grade their peers; thereby removing the grading load from the TA entirely. If the instructor wants to save work for his TA then maybe he should use such a grading policy. But isn't the point of a TA to help the instructor with work such as grading, not sit around and twiddle his thumbs and get a free ride? I'm also a TA and I don't get a free ride. The TA for this course shouldn't get a free ride either.

So not only am I stuck having to deal with this class, but now I also get to find out on which side of the lucky/unlucky line I reside on. If it is the lucky side I better run to Vegas quick, because I'll make more there in a weekend than I ever could in a lifetime as a PhD. If it is the unlucky side then I have a lot of studying to do this winter so I can pass the oral exam for this qualifier component, as I failed the class. *sigh*

More interestingly, even if I could find and document such a case of one student passing while the other failed, yet the failing student did better overall on the homework than the passing student, I would be unlikely to win a petition on the subject to the graduate curriculum committee, as such a decision could possibly void a number of grades given for this class over a number of years. Talk about tipping over the apple cart.

So the short of it is: Life is a bitch. And any grade earned in this course is pretty much irrelevant, as only 6% of your grade actually matters but 30% of the grade is randomly determined. Uhm yea, I'm motiviated to care about this material.

I might as well just flip a coin to determine if I would make a good PhD student.

*flip* Damn. Tails. I guess its time to pack up, go home, and get a real job.


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