In other countries, such as Finland and Japan, where students outperform those in the U.S. in international tests such as PISA and TIMMS, collaboration among teachers is an essential aspect of instructional improvement. The problem is not that American teachers resist collaboration. Scholastic and the Gates Foundation found that nearly 90 percent of U.S. teachers believe that providing time to collaborate with colleagues is crucial to retaining good teachers.

So what would it take structurally to enable teachers to work collaboratively for improved learning outcomes?

Answering this question demands changes in some longstanding American public school structures. Perhaps the most important change is in school curricula. One of the key differences between public education in the U.S. and elsewhere is the lack of a common curriculum. In other countries common curricula unite the work of teachers, school leaders, teacher educators, students, and parents. With a common curriculum there is agreement about what students are expected to learn, what teachers are to teach, what teacher educators are to instill in potential teachers, and what tests of student learning should measure.

A common curriculum for the nearly 100,000 K-12 schools in the U.S. could be a major step towards productive teacher collaboration. It would align the scope and sequence of what should be taught and learned, and teachers could collaborate with one another on lessons day by day. They could look at student work and assessments of student learning of that curriculum, and could coordinate their instruction to remediate and enhance student understanding.

There is some hope that this could actually come to pass. Today, 45 states and the District of Columbia have committed to the Common Core, a set of curricular standards that are meant to drive instruction and assessment. While the Common Core is not an elaborated curriculum, it is definitely a move in the right direction.

However, even the best curriculum is not self-enacting. Time and money need to be invested to support teachers' understanding of the curriculum and to develop an ethos of collaboration within schools. Also needed are ongoing professional development programs to support teachers' substantive work together.

While we are making good headway in support of these efforts, one problem looms. A number of contemporary reformers have put great faith in the idea that teacher competition (e.g., merit pay) can dramatically improve educational outcomes. The jury is still out regarding the effectiveness of such reforms, but we greatly fear that such policies will undermine teachers' collaborative work. Ironically, competitive teacher assessment schemes could reinforce teacher isolation. If teachers are competing with one another for merit pay, why should they collaborate with one another? They might as well go back behind their closed doors.