Using Advanced Placement to Assess Teachers

There is increasing evidence that parents are using the scores of past students on advanced placement tests to assess a teacher's ability. Here is one link, thanks to JC.

Peter Johnson, chair of the social studies department and AP teacher at Brophy College Preparatory in Phoenix, said, “AP teachers should face some sort of accountability, and having their pass rates become public knowledge can be an effective motivating tool. I know this may sound harsh, but I have known quite a few AP teachers during my career as both a high school student and teacher who have taught AP courses only because they figure that fewer disciplinary problems will arise in such courses, or because they will receive an additional financial stipend for it.’’

Here is another link to a piece by the same journalist.

"The long-term test results of similar cohorts of students taking the same teacher's AP or IB class reflect a good part of the teacher's ability, in the same way that mortality rates for a surgeon and investment results for a financial adviser reflect on those professionals' competency," said Robert Rosenfeld, a parent in Montgomery County. "Although teachers cannot be held to guarantee test results -- as if students are empty vessels waiting to be filled without effort on their part -- nonetheless teachers can be held to deliver effective instruction."

Using AP results to assess teachers is a good start. But there are two big problems:

1. Teachers have an incremental effect, not a total effect. The important question is "What is the value added by one teacher vs. another?" If the starting points and abilities are, on average, the same for all the students, then maybe AP results are a good proxy for teaching ability. But if different students have different abilities and/or different starting points, using AP results will give distorted assessments of teaching abilities.

2. Furthermore, not only will using AP results to assess teaching ability induce teachers to try to get students who will receive low scores to drop out of the AP classes, but it will also induce them to recruit the better students into their classes (sort of the way top universities try to attract the best students).

After all, people respond to incentives.