This publication shares expert insights to support holistic, equity-driven approaches to measuring program quality. Guided by a workgroup of early childhood measurement experts, this two-part guide brings fresh perspectives and new ideas for leaders to consider when evaluating programs that serve young children and families. Central to the report is the belief that an early childhood program cannot be considered high-quality without equity of access, experience, and opportunity, resulting in equitable outcomes for all children and families. The guide recommends the use of quality measures to reflect the full range of experiences that children need to thrive, as well as the supports required to provide those experiences, such as public systems, professional development approaches, teacher pay, and other factors. The guide is framed by the principles of ideal learning environments for young children, a set of nine essentials drawn from child development research, and high-quality pedagogical approaches. Part one of the guide explores how policy decisions about what is measured (in classrooms, programs, and systems), how it is measured, and how the information is used can have significant implications for addressing or exacerbating inequities within programs and systems. It suggests that explicit attention be paid to how race, culture, language, and bias play out when considering these issues. To aid in the development of equitable and effective quality measurement, the guide emphasizes Fundamentals of Quality Measurement for policymakers alongside questionnaires to help guide their decision-making. Part two of the guide shows how the Principles of Ideal Learning framework can guide a holistic picture of program quality. It provides an overview of the current state of measurement for each of the nine principles, and gives examples of measurement tools that may be used to capture elements of each. This section and the attached Appendix provide useful information for policymakers and educators about available tools and methods to help them dig deeper into each of the principles and explore options to guide program improvement.