"Students' Mastery of Learning Outcomes"

I read that phrase today here.

I want to point out something: students master skills, games, texts, the weather (if they're divine), and all sorts of other things.

But people don't "master" "outcomes". It's just not the sort of thing that gets mastered, because outcomes are just the results of mastering other things.

Some might say that I'm being nitpicky. But words mean things. And if you can't speak/write clearly about what it is you're doing, odds are high that you don't really have a clear idea of what you're doing in the first place.