This report presents findings of a review of survey estimates of the prevalence of disability in Britain and the definitions of disability used in government social surveys. The study examines the relative merits and methodological robustness of a variety of estimates of the prevalence of disability produced by surveys. The review involved: A technical review of the existing surveys and estimates; A consultation exercise involving key stakeholders and users of disability estimates to explore their views on measurement and definitional issues of disability; An exploration of what might be done to ensure consistency over time of estimates and definitions of disability in Great Britain.