Understanding Society is the UK Household Longitudinal Study and is the largest longitudinal household panel study of its kind. We collect data from the same individuals in the same UK households, year on year, to build a picture of both stability and change across society. We ask questions about our respondents' economic circumstances, their attitudes, lifestyle, family relationships and employment. We are also a bio-social with both objective and subjective measures on health. The data produced by our study leads to research which informs policy and helps to shape the future of the UK. Funded by the Economic and Social Research Council, Understanding Society operates under the scientific leadership of the Institute for Social and Economic Research based at the University of Essex.