The inability to engage in substantial gainful activity (SGA) by reason of any medically determinable physical or mental impairment that can be expected to result in death or to last for a continuous period of not less than 12 months. (Special rules apply for workers aged 55 or older whose disability is based on blindness. The
Individuals are considered to be disabled only if their physical or mental impairment(s) is of such severity that they are not only unable to do their previous work but cannot—because of their age, education, or work experience—engage in any other kind of substantial gainful activity that exists in the national economy, regardless of whether such work exists in the immediate area in which they live, or whether a specific job vacancy exists for them, or whether they would be hired if they applied for work.
The SGA criterion does not apply to children under age 18 in the Supplemental Security Income program. The standard for them is a medically determinable physical or mental impairment that results in marked and severe functional limitations.