The education research of recent years has pointed overwhelmingly to the importance of teachers. Perhaps more than anything else – quality of principal, size of school, size of class – the strength or weakness of classroom teachers influences how much students learn and even how they fare later in life.
The great unknown is how to improve teacher quality, be it by attracting more good teachers, weeding out more bad teachers or helping teachers become better at their craft.
A new study released on Thursday, offers powerful if still tentative evidence that teacher-evaluation programs can play an important role. The study is especially notable because past research about evaluation programs suggested they had little effect. The new paper, however, studies an evaluation program – called Impact, in the District of Columbia school system – that is far larger, with bigger rewards and stiffer penalties, than most programs.
Impact, which began under Michelle Rhee while she was chancellor, has been a hotly debated program, and the new study is sure to attract attention from both supporters and critics of teacher evaluation. New York state’s plan to begin evaluating teachers has also been the subject of intense praise and criticism, as have such programs elsewhere.