The present report, prepared by the Population Division of the Department of Economic and Social Affairs, reviews the current status of demographic evidence and its capacity to support monitoring of the Sustainable Development Goals. It focuses on the core systems generating demographic data and describes how the "data revolution" has already improved their performance and the potential for accelerating such improvements. In addition, the report underscores that open access to anonymized microdata and routine use of geo-referencing in data collection are necessary to expand the use of demographic data. Geo-referencing makes possible the integration of diverse datasets and facilitates disaggregation and the incorporation of big data in analyses and modelling. The report also highlights the role of institutions producing consistent and comparable sets of demographic indicators essential for monitoring the Sustainable Development Goals globally.