Why is accountability always about teachers?

I posted this piece in the Brookings ‘Evidence Speaks’ series. The question is why so much accountability in K-12 education focuses on how teachers are performing–their students’ test scores, their classroom observations, their ratings–when most of the real decisions in K-12 education affecting classrooms are made by administrators.  The lack of balance means teachers are held accountable for decisions made by others, which surely must sap morale and be a source of real frustration.