How do I know? Well I was talking to 2 of the kids I teach, and they've got into university. Now I hear you saying "Now just hold on a minute there Jimbo, they might have had something to do with it don't you know?"
In response, I say nay nay. Trust me when I say that these two students have to be two of the sorriest sacks of spuds I've ever taught Chemistry 'A'-Level to. They both got a C in GCSE Chemistry. They both got an E at AS-Level Chemistry (before I taught them I hasten to add), and yet, one's got into Penn State, and the other's got into the University of Miami, and I have no idea why.
Now don't get me wrong, their references were things of beauty. Not one word in them is a lie, but if you read them, you'd spot that I said pretty much nothing about them Chemistry, and that should have set alarm bells off somewhere, shouldn't it?
As an example, I described one student as the someone "who willingly participates in class discussions," (she does, I'll give her that) and "gives memorable answers" (we were revising the shape of molecules, and I asked her what we called a three sided shape. Her response, after "I don't know" was "a tri-sides trigonal polygon.").
I mean come on, how on Earth has she got in anywhere good?