The push for globally-comparable measures of learning is truly underway, with work well advanced through the Global Alliance to Monitor Learning (GAML) to develop common metrics to benchmark student performance in reading and mathematics. The development of common metrics is fundamental to the achievement of Sustainable Development Goal 4 (SDG 4): ensure inclusive and quality education for all by 2030. Common metrics are crucial if we are to obtain a comprehensive and comparable picture of how well children are learning what they need to learn – the ‘quality’ part of the SDG 4 equation. As part of their collaboration to support global efforts to reach SDG 4, the UNESCO Institute for Statistics (UIS) and the Australian Council for Educational Research (ACER) through its Centre for Global Education Monitoring (GEM) are developing the tools, methods and approaches to build comparable indicators of learning outcomes. At the heart of the collaboration lies the development of common learning metrics – also known as the UIS reporting scales – to describe and quantify learning progress in reading and mathematics.