I fail the potential of my assessments continuously.
I disaggregate them to such an extent that I can recall, even months down the line, that Alex confused adjacent with opposite in trigonometry, that Suzanne added before she multiplied in the order of operations, and that Derek thought 2x + 3 was 5x.
Several students came within an inch of mastering "sine/cosine/tangent" last week. I had a list. I knew how to remediate their weaknesses but I carried that list into class with me last week and I carried it out again having done nothing.
I don't know how to make time for this, how to structure my class so that our momentum is forward-going, so that every student has something challenging on her desk, so that I can take some time to remediate the right skills with the right students.
I am a pretty-good marksman too hurried to load his rifle.
[BTW: I post the test questions on the next opener. Most kids run through the problem like it's the first time they've seen 'em. I know which students to talk to and about which concepts. Halfway through I pass back their tests and they compare their work on the openers to the work on their tests. This will do for a start.]