What "Please give more detail" means

Students are often frustrated when I mark their papers "please give more detail." I admit the comment doesn't tell you much about what sort of detail I would like to see (but it does fit in the margin nicely). Here is a guide to the kinds of ways one can add "detail" to a paper without simply repeating yourself.

Allan Bloom has posited a "taxonomy of educational objectives" that helps us discriminate different kinds of detail. Underneath each of these sorts of detail, I give an explanation of it and an example. Each single example sentence would never stand by itself in a paper, but represents what might be the topic sentence of a paragraph. Stuff towards the top of this list is detail that is less impressive than stuff towards the bottom.