Measuring where students are at in their learning is critical for determining whether the world is on track to meet Sustainable Development Goal (SDG) 4. ACER’s contribution to SDG 4 is spearheaded through the work of the GEM Centre, a long-term partnership with the Australian Government's Department of Foreign Affairs and Trade (DFAT). At the core of the GEM Centre's contribution is the development of technically sound and internationally comparable learning metrics that enable education stakeholders to align assessment systems with global SDG monitoring and reporting.