This article on LLN counts – 26TEN study into the value of investing in improving adults’ literacy and numeracy skills summarises historical research that explains why “…the challenges presented by adults with low basic skills may lead to Australia being left behind…” (OECD, 2017, p. 9) and outlines how hard it has been historically, to gather data that shows the impact of adult literacy and numeracy programs on individuals, organisations and communities. It also introduces recent research findings that show a whopping 520% return on investment in adult literacy and numeracy programs.