Book excerpt: The Organisation for Economic Co-operation and Development (OECD) and the United Nations Development Programme (UNDP) work together to monitor progress in using the principles for effective development co-operation. In 2018, data was collected by 86 partner countries and territories, in collaboration with more than 100 development partners, to serve as the basis for this work and provide evidence. By highlighting where progress has been made and where challenges remain, the work helps governments and their partners strengthen collective action towards the 2030 Agenda for Sustainable Development.