Principals are in a paradoxical position. On one hand, they're called on to use research-based strategies to improve student achievement. On the other, they're increasingly required to micromanage teachers by observing in classrooms and engaging in intensive evaluation. The authors point out that these two positions are at odds with each other. In fact, research has shown that teacher evaluations, along with many other mandated practices, have not improved teaching or learning. If principals want to improve student achievement, rather than focus on the individual inspection of teaching, they must focus on the collective analysis of evidence of student learning. The most powerful strategy for improving teaching and learning is creating the collaborative culture and collective responsibility of a professional learning community. The effort to improve schools through tougher supervision and evaluation is doomed to fail, the authors note, because it asks the wrong question. The question isn't, How can I do a better job of monitoring teaching? but, How can we collectively do a better job of monitoring student learning?