The Core Conceptual Framework for Professional Development includes five key components. They are collective participation, active learning, coherence with policy, extended duration, and a focus on learning new skills in the context of building content knowledge. While specific content covered in the teacher professional development (PD) varied, all programs were required to be developed with a focus on collective participation, active learning, coherence with policy, extended duration, and building content knowledge in order to be funded by the state initiative. Formative evaluation means teachers, administrators, and/or PD providers collaboratively examine standardized and informal data sources to inform the direction and assess the effectiveness of PD implementation. The concept shared in this chapter is important to build a plan for PD that includes the key components of effective PD. It is clear that district level PD has historically focused on very general skills and strategies that all teachers are required to attend.