A person with a physical, mental, or emotional condition lasting six months or more, who has difficulty in doing any of the activities that are typically completed while working at a job or business (Lee & Erickson, 2008).

Erickson, W., & Lee, C. (2008). 2007 disability status report: United States. Ithaca, NY: Cornell University Rehabilitation Research and Training Center on Disability Demographics and Statistics.