Teacher quality -palooza continues. Yesterday I discussed the multiple goals of education and what it means for a teacher to be good.
Today I want to focus on how the debate has overemphasized the contributions of individual teachers without thinking about the ways that schools function like organisms. No teacher is an island. In multiple ways, schools and colleagues enable and constrain the work that a teacher does in his or her own classroom. There are three key points to this argument:
1) Teachers are interdependent
This means two things. First, teachers provide instructional support to their peers. When Mrs. Jones heads down to Mrs. Scott's room to ask for help, trade ideas, talk over what to do about a difficult student, or plan a lesson together, we see evidence of the interdependence that makes schools a unique enterprise. To reduce teacher effectiveness to a measure of what one teacher does in her own classroom ignores that teaching is, in the best circumstances, a collective accomplishment. Identifying these "peer effects" formally is difficult for a host of boring methodological reasons, but nonetheless something that educational research needs to do.
The second issue applies specifically to middle and high schools, where students are taught by multiple teachers. When Mrs. Jones, the reading teacher, improves Mikey's reading skills so that Mrs. Scott can teach him how to do word problems, we see that no teacher is an island. When Mrs. Scott gets Mikey's attention problems under control so Mrs. Jones can get Mikey to sit still and read, we see another example of interdependence.
We don't think about interdependence because we are deluged with images of individual teachers administering vigilante justice in unruly schools (think "Dangerous Minds"). Those who haven't spent much time in urban schools assume that teachers are isolates. But I would submit that even in the toughest schools, there are teachers working together in ways that violate the independence assumption of the teacher quality debate.
2) Teachers play many roles in a school
There is an oft-cited maxim that returns to experience plateau after five years (which is true), with the implicit assumption that more experienced teachers aren't adding more value (which is not). Experienced teachers often serve as anchoring forces in addition to teaching students in their own classrooms. Some of these functions sit under the collaboration and mentoring points discussed above, but others involve schoolwide leadership.
If we opt to hire and reward teachers based only on their own students' performance, it follows that we would save a lot of money by shedding more experienced (and thus more expensive) teachers. Indeed, this is a fear of many teachers in New York City, which will begin allocating dollars, rather than teaching positions, to schools.
Thinking about returns to experience this way would be a mistake even for those concerned only with student achievement, as pulling out the core of our schools - experienced educators - may destabilize schools altogether.
3) Schools, as organizations, create the conditions for the work individual teachers do in their classrooms: Let's imagine that we want to compare the teachers in two different schools for the purposes of merit pay or job evaluations. In School A, resources are flush, class size is small, and the hallways are quiet. In School B, there are no books, class size is 50% larger, and the school is chaotic.
If we are going to make across school comparisons of teachers, we need to take into account that individual schools can make teachers more or less effective. What we really need to know is how Mrs. Jones at School A would have performed if she was a teacher at School B. Economists call this "firm-specific capital"; sociologists call this a "school effect." Irrespective of what we call it, we need to take school conditions into account when we think about comparing teachers across schools.