A person must not only be unable to do his/her previous work but cannot, considering age, education, and work experience, engage in any other kind of SGA which exists in the national economy. It doesn't matter whether such work exists in the immediate area, or whether a specific job vacancy exists, or whether the worker would be hired if he/she applied for work. The worker’s impairment(s) must be the primary reason for his/her inability to engage in SGA.