faul_sname comments on Shut Up And Guess - Less Wrong

79 Post author: Yvain 21 July 2009 04:04AM

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Comment author: SoullessAutomaton 21 July 2009 11:15:28AM 13 points [-]

I vaguely recall reading an anecdote about a similar testing scheme where you had to give an actual numerical confidence value for each answer. Saying you were 100% confident of an answer that was wrong would give you minus infinity points.

I bet that would be even less popular with students.

Comment author: bill 21 July 2009 02:48:57PM *  20 points [-]

I've given those kinds of tests in my decision analysis and my probabilistic analysis courses (for the multiple choice questions). Four choices, logarithmic scoring rule, 100% on the correct answer gives 1 point, 25% on the correct answer gives zero points, and 0% on the correct answer gives negative infinity.

Some students loved it. Some hated it. Many hated it until they realized that e.g. they didn't need 90% of the points to get an A (I was generous on the points-to-grades part of grading).

I did have to be careful; minus infinity meant that on one question you could fail the class. I did have to be sure that it wasn't a mistake, that they actually meant to put a zero on the correct answer.

If you want to try, you might want to try the Brier scoring rule instead of the logarithmic; it has a similar flavor without the minus infinity hassle.

Comment author: faul_sname 19 January 2016 10:04:31AM 0 points [-]

What does 0.01% on the wrong answer get you?

Comment author: gjm 19 January 2016 11:26:06AM 0 points [-]

Depends what you do with the other 99.99% and the other three answers, I assume.

In a two-answer scenario, if I'm understanding bill's version of the log scoring rule correctly, giving p=0.9999 to the right answer and p=0.0001 to the wrong answer should get you [log(0.9999)-log(1/2)]/log(2) ~= 0.99986 points. With four answers, giving p=0.9997 to the right answer and p=0.0001 to each of three wrong answers should get you [log(0.9997)-log(1/4)]/log(4) ~= 0.99978 points.