Harder questions (e.g. around 50% average instead of around 90% average) seem better for differentiating students’ understanding for at least two reasons: -The graph of percent of students who got a question correct as a function of the difficulty of the question tends to follow a sigmoid-ish curve where the fastest increase is around the middle. -Some of a students’ incorrect answers on the test are going to come from sources that (a) the student can prepare to mitigate (b) aren’t caused by lack of whatever students should be being tested for (e.g. questions with ambiguous meanings, questions that require an understanding of a niche framework that is never used outside of the curriculum, questions that have shortcuts that the teacher didn’t recognize, etc). Ideally, we don’t want any differences in student test results to be based off of these things, but harder tests at least mitigate the issue since understanding (or whatever stuff which we do want students to spend time on) becomes a more important cause for incorrect student selections. (Neither of these are hard-and-fast-rules but the general pattern seems to hold based on my experience as a student.)
Harder questions (e.g. around 50% average instead of around 90% average) seem better for differentiating students’ understanding for at least two reasons:
-The graph of percent of students who got a question correct as a function of the difficulty of the question tends to follow a sigmoid-ish curve where the fastest increase is around the middle.
-Some of a students’ incorrect answers on the test are going to come from sources that (a) the student can prepare to mitigate (b) aren’t caused by lack of whatever students should be being tested for (e.g. questions with ambiguous meanings, questions that require an understanding of a niche framework that is never used outside of the curriculum, questions that have shortcuts that the teacher didn’t recognize, etc). Ideally, we don’t want any differences in student test results to be based off of these things, but harder tests at least mitigate the issue since understanding (or whatever stuff which we do want students to spend time on) becomes a more important cause for incorrect student selections.
(Neither of these are hard-and-fast-rules but the general pattern seems to hold based on my experience as a student.)