The English Longitudinal Study of Ageing is an interdisciplinary data resource on health, economic position and quality of life as people age. ELSA is the first study in the UK to connect the full range of topics necessary to understand the economic, social, psychological and health elements of the ageing process. The aim of ELSA is to explore the unfolding dynamic relationships between health, functioning, social networks and economic position. It is in effect a study of people's quality of life as they age beyond 50 and of the factors associated with it.