20 CFR § 220.142 - General information about work activity.
(a) The nature of the claimant's work. If the claimant's duties require use of the claimant's experience, skills, supervision and responsibilities, or contribute substantially to the operation of a business, this tends to show that the claimant has the ability to work at the substantial gainful activity level.
(b) How well the claimant performs. The Board considers how well the claimant does his or her work when the Board determines whether or not the claimant is doing substantial gainful activity. If the claimant does his or her work satisfactorily, this may show that the claimant is working at the substantial gainful activity level. If the claimant is unable, because of his or her impairments, to do ordinary or simple tasks satisfactorily without more supervision or assistance than is usually given other people doing similar work, this may show that the claimant is not working at the substantial gainful activity level. If the claimant is doing work that involves minimal duties that make little or no demands on the claimant and that are of little or no use to the claimant's railroad or non-railroad employer, or to the operation of a business if the claimant is self-employed, this does not show that the claimant is working at the substantial gainful activity level.
(c) If the claimant's work is done under special conditions. Even though the work the claimant is doing takes into account his or her impairment, such as work done in a sheltered workshop or as a patient in a hospital, it may still show that the claimant has the necessary skills and ability to work at the substantial gainful activity level.
(d) If the claimant is self-employed. Supervisory, managerial, advisory or other significant personal services that the claimant performs as a self-employed person may show that the claimant is able to do substantial gainful activity.
(e) Time spent in work. While the time the claimant spends in work is important, the Board will not decide whether or not the claimant is doing substantial gainful activity only on that basis. The Board will still evaluate the work to decide whether it is substantial and gainful regardless of whether the claimant spends more time or less time at the job than workers who are not impaired and who are doing similar work as a regular means of their livelihood.