Many adults in OECD countries have low language, literacy and numeracy (LLN) skills. The consequences of these low foundation skills span the economic, health and social well-being of individuals, families and communities. Investment in this sector of adult education is therefore crucial. This study looks specifically inside the programmes for adult LLN learners, with a focus on formative assessment. Drawing upon evidence gathered in country reports, exemplary case studies and international literature reviews, it examines the impact and implementation of different teaching, learning and assessment practices for adult LLN learners; the way innovative programmes address the very diverse needs and goals of this population; and the policies that support or hinder effective practice. This book provides a strong foundation for understanding the fundamental issues at stake in the adult LLN education, and can guide future policy, practice and research. A companion report which studies formative assessment in lower secondary schools was published in 2005 under the title Formative Assessment: Improving Learning in Secondary Classrooms.