This document discusses the importance of teacher collaboration and sharing ideas as a means to identify and spread best practices. It argues that collaborative professional development approaches, like professional learning communities and networks, are more effective than traditional lecture-style models. When teachers work together to achieve shared goals and learn from each other, it has a greater positive impact on student achievement outcomes. For professional development to be most effective, it should establish a shared agenda, provide time for teachers to learn from each other, and allow flexibility for personal interests.