I have a friend who is a high school teacher, and I was shocked to learn how they evaluate him.  (No idea how true this is for other schools).<p>They compare the standardized test scores of this years group of students with those of last year&#x27;s.  If these students do better than those, he must have improved, and if they do worse, he must have slacked.<p>Now, he&#x27;ll have between 20-100 students each year.  Any teacher will tell you that the variation between one year&#x27;s group of students and the next is considerable.  (indeed, among my teacher friends I&#x27;ve learned it&#x27;s a major point of gossip - not individual students, but the collective lot)<p>This seems insane to me.  Why not compare this years students with THOSE SAME STUDENTS&#x27; SCORES from last year?  Or find something else less likely to be so &quot;swingy&quot;.