Abstract: Current models of health and well-being emphasise the importance of communities, with the role of social connectedness, service access and community participation in healthy ageing increasingly acknowledged. Whilst the importance of social participation is now widely recognised, our understanding of who participates, how and why, especially in later life, is more limited. Two key challenges to understanding social participation are its conceptualisation and its measurement. We do not consider social participation to be a binary construct, but instead conceptualise it as multidimensional, with people participating in some domains and not others. As needs change with age how we conceptualise participation will also change, modifying how we operationalize it across the life course. This presentation will discuss the conceptualisation of social participation in later life, and how it has been operationalized in order to understand the determinants and consequences of social participation in waves 1-3 of Understanding Society – the UK Household Longitudinal Study. We take the view that it is important to exclude precursors or outcomes, such as income and health, in our definition of social participation if we are to advance understanding of the drivers and consequences of a lack of social participation for older adults. The presentation will conclude with some reflections on the challenges and opportunities of secondary data analysis.