The Network on Labour market, economic, and social outcomes of learning (LSO Expert Network) has diligently worked on the selection of indicators for monitoring adult learning policies. Their inaugural theoretical framework on adult learning, published in 2013, covered a broad spectrum of policy areas. This comprehensive scope reflected both the focus of existing data sources and the challenges encountered in data collection efforts. Over the past decade, significant policy shifts have occurred, reshaping adult learning systems both domestically and internationally. Concurrently, there have been improvements in the availability and frequency of data pertaining to adult learning. In response to these developments, this working paper presents an updated theoretical framework on adult learning, aiming to enhance the identification of statistical data concerning adult learning systems and facilitate the selection of pertinent indicators for monitoring purposes. Additionally, the paper offers detailed insights into national priorities and practices within this domain.