Additional samples of 1 500 households in both Scotland and Wales were added to the main sample in 1999, and in 2001 a sample of 2 000 households was added in Northern Ireland. These same individuals are re-interviewed each successive year and, if they split-off from original households to form new households, they are followed and all adult members of these households are also interviewed. Variables include information on income, poverty, social exclusion and other living conditions.