Estimates of prevalence, demographic characteristics and social factors among people with disabilities in the USA: a cross-survey comparison.

Objective: A national priority for disability research in the USA is the standardised identification of people with disabilities in surveillance efforts. Mandated by federal statute, six dichotomous difficulty-focused questions were implemented in national surveys to identify people with disabilities. The aim of this study was to assess the prevalence, demographic characteristics and social factors among people with disabilities based on these six questions using multiple national surveys in the USA.