The students paid me nothing. The university provides some TAs, that's it. But even if they gave me all of that money in cash to spend, this would be totally impossible.

I'm supposed to grade a student based on 1 conversation? Do you know how grading and teaching work? Can you imagine the complains that would come out of this process? How unfair it is to say that you have one 15 minute shot at a grade?

But fine, even if we say that I can grade someone based on 1 conversation. What am I supposed to ask during this 15 minute conversation? Because if I ask the every student the same thing, they'll just share the questions and we're back to being useless.

So now I need to prep unique questions for 200 people? Reading their background materials, projects, test results, and then thinking of questions? I need to do that and review it all before every session.

Even with a team of TAs this would be impossible.

But even if I do all of this. I spend hours per student to figure out what they did and know. I ask unique questions for 15 minutes so that we can talk without information leakage mattering. You know what the outcome will be? Everyone will complain that my questions to them were harder than those that I asked others. And we'll be in office hours with 200 people for weeks on end sorting this out and dealing with all the paperwork for the complaints.

This is just the beginning of the disaster that this idea would be.

It's easy to sit in the peanut gallery and say "Oh, wow, why didn't my arm surgery take 10 minutes, they just screwed two bones together right?" until you actually need to do the thing and you notice that it's far more complex than you thought.

> The students paid me nothing.

Well gee, there I was thinking they were paying $27,480 per year for "tuition"

Later, people learned that and started to buy diploma: faster, cheaper, no risk of failing the final exam.