In the first of two related articles, this article attempts to explain what can be learnt from international assessments of adult literacy and numeracy skills, and why there is value and crucial and important lessons for all educators, and others, from the work underpinning these empirically based research endeavours. Whilst some criticism of the surveys is understandable and to be expected, this often blinds readers and the LLN sector from reading between and behind the lines and seeing what value can be generated, gained and learned from such investigations, data and research. The article describes the theoretical frameworks and quality assurance processes that go into the development of such assessments and that their results must be taken seriously in relation to improving the standards of literacy and numeracy, not only for the individual, but also for society and the workforce.