Basic education is essential if societies and economies are to thrive and become sustainable in challenging times. However, many people have never had an opportunity to benefit from education and many others leave the initial phase of education without attaining the level of proficiency in literacy and numeracy needed to participate fully in society. The scale of the problem is large yet qualifications systems in many societies still limit their focus to qualifications acquired formally and do not offer opportunities for young people and adults to re-engage in learning pathways that have been interrupted. In order to avoid a significant loss of human potential, the non-formal and informal learning of young people and adults should be made visible and valued. Systems should be in place to ensure it is recognized, assessed and accredited. The UNESCO Institute for Lifelong Learning (UIL), in partnership with UNESCO's Section of Partnerships, Cooperation and Research, has undertaken a number of comprehensive analyses of policy and practice in this area, which have highlighted the need to focus on the recognition, validation and accreditation (RVA) of youth and adult basic education. This report summarizes the research and policy dialogue of an international expert group invited by UNESCO to three meetings in 2016. It focuses on three themes -- principles, policy and practice -- and provides examples of how the issue is being approached across the world. It offers 12 conclusions, based on the evidence considered by the expert group, and proposes a number of key messages for stakeholders in Member States, including policy-makers and the research community.