Rubrics

I'm reading the beginning of a book titled Rethinking Rubrics in Writing Assessment and written by Maja Wilson. The forward, the part I'm reading right now, is by Alfie Kohn. Here's an interesting quote: ". . . students whose attention is relentlessly focused on how well they're doing often become less engaged with what they're doing."
Kohn is decidedly anti-rubric. I wonder. . . .