The FACS, formerly known as the Survey of Low Income Families (SOLIF), was a series of annual panel surveys designed to compare the living standards and outcomes of British families across the income distribution. The study began in 1999 with a survey of more than 4,000 lone-parent families and low-income couples with dependent children living in Great Britain. From wave 3 (in 2001) onwards, the survey was renamed FACS, and the sample was expanded to include higher-income families, resulting in around 8,500 families in wave 3. There were 10 annual waves of the survey until 2008, and the longitudinal sample was refreshed at each wave with a booster sample of new families to ensure cross-sectional representativeness in each year.