The authors outline the potent relationship between continuing professional development (CPD), teacher efficacy, and student learning outcomes in the context of a major reform of middle years teacher work in Queensland, Australia. The authors explore core features of effective teacher CPD, including content focus, active learning, coherence, duration, and collective participation. Further, they outline the development of a tool that enables comprehensive feedback for those who design and deliver CPD on all of these dimensions to ensure the work they undertake is effective and will have the potential to lead to improved student outcomes. The purpose of this tool is to evaluate Levels 1 and 2 of Guskey's (2002) critical levels of professional development. The tool was administered at the completion of 11 unique CPD events with more than 450 participants, with numbers varying from small to large groups, and from one hour to full day CPD events. Data generated were used by the facilitators for three purposes: (1) to evaluate the effectiveness of the CPD they conducted through the participants' reactions (Level 1) and their learning (Level 2), (2) to gain insights into the comprehensiveness and usefulness of the instrument to capture the core features regarded to be critical for effective teacher professional development (i.e., as a reflective tool to improve future practice), and (3) as a framework for effective CPD design. The process has enabled the development of a tool that will serve as a useful addition for those who are interested in designing CPD using an evidenced-based framework and evaluating their CPD program to consider its effectiveness in terms of the participants' reactions and learning.