Adult numeracy and literacy skills are key to transforming lives, promoting social inclusion and contributing to sustainable societies. Achieving an optimal return on investment with regard to the development of adult skills and competencies requires the collation of comprehensive data to assess what people know, what they do with what they know, and the extent to which they are equipped to sustain themselves in the twenty-first century. To help policy-makers generate these data, the UNESCO Institute for Lifelong Learning (UIL) has published a new policy brief focusing on direct assessments of adult skills and competencies. While collective efforts have led to continuous progress with respect to increasing literacy rates, global data on literacy, based on conventional proxy indicators, remains insufficient to offer a comprehensive picture of the literacy challenge. Currently, only 13 per cent of the world's countries have data on literacy and numeracy skills based on direct measurements (Subosa and West, 2018).