A review of the research on teacher professional development identified an emerging consensus on important contextual and implementation characteristics that can promote or inhibit teachers' use of new knowledge and skills in their classroom practice. Findings suggest that professional development is best viewed as one component in an overall system that also requires alignment among tests, policy, and curriculum. Within this context, research has shown that effective professional development tends to have the following elements: Content and content pedagogy focus; coherence; active learning; collective participation; and duration, including at least 30 contact hours distributed across a time span of at least a year.