Exit Slip: Are marks accurate?

I think marks are incredibly inaccurate a lot of the time. Obviously, it depends on how and what the teacher is marking, but from my own high school experiences in math, marks and grades really only showed how good you were at reproducing something on a specific day. The especially only catered to a few students who were able to perform in the manner that was being graded. In high school math, I regularly got high 90s in every class, in fact, I'm pretty sure I got 99 once. This in no way showed that I was "exceptionally above expectations". I wasn't. I was comprehended material and steps well, but I wasn't extending. I wasn't inquiring into connections and deeper concepts. I wasn't tying ideas together or exploring the math. I was good at noticing patterns, fitting formulas, and improvising when things got funky. I was good at test-taking strategies and test time management. My grades did not accurately reflect my actual conceptual understanding. In the same way, my classmates who desperately needed more time on tests to fully work through their ideas, were being drastically dis-served by the long test, short period format that our teacher went with. Our teacher clearly valued being able to quickly recognize what the question was, what it wanted, and how to produce that answer quickly. This, I would argue though, says absolutely nothing about a student's real ability in math. My high school peers were never given a chance to experience math outside of a test format, and thus were never able to develop and show their learning in a format that fit their brains. And thus their grades never accurately reflected what their math understanding was.