The Principal Difference — this blog, by the National Association of Secondary School Principals, doesn't shy away from raising important issues such as uncovering myths of student engagement or if
elementary teacher bias discourages girls from math and science.
If value - added estimates do not fully account for unobservable differences in students, then we would expect to see this pattern — the variance in
teacher value - added is greater at the
elementary level perhaps because of
biased estimates.