I don't remember if I've re-posted XKCD comics before. But Randall Munroe is one of my favorite webcomic authors, and he often has keen insights.
Friday's was especially timely. As I mentioned, on Thursday and Friday I went to a training (along with an extraordinary number of St. Joseph County's best and brightest) on Marzano's Formative Assessments and Standards-based Grading. One of the key ideas of Thursday's training is that a traditional, letter-grade-based-on-a-100%-scale grading system is almost useless, and that averaging grades together is no way to show a student what she has learned. (Friend and regular commenter Ray told me so in a comment in an earlier post.)
Friday morning's XKCD: