Article published in the Journal of Human Development and Capabilities Volume 17, 2016 - Issue 4: Investing in Early Childhood Development. Published abstract: "Children’s early development serves as the foundation for later health, learning and well-being. The inclusion of early childhood development (ECD) in the Sustainable Development Goals implies that countries must report on the percentage of children under 5 years of age who are “developmentally on track.” This note briefly reflects on the history of global ECD goals and their measurement and outlines the challenge ahead: creating a workable strategy for ECD measurement that balances the need for national relevance with globally comparable data. The global variation in the timing and nature of early childhood skills acquisition presents an important opportunity as countries set their own standards for what it means to be developmentally on track. Country-driven measurement and standard setting, derived from measurement approaches that meet international expectations for quality, can have an important influence on policy and practice. Countries can measure the development of their youngest citizens in a way that is most relevant and useful to them, so that they may use those data to ensure that all children have the opportunity to fulfill their potential."