The first is a social insurance program, wherein an individual with a disability receives a cash payment based on their own earnings or those of a parent who has retired or died. The latter is an income maintenance program for aged, blind, or disabled individuals or couples with low income and few resources. Cash payments are not predicated on prior contributions to the Social Security Fund.
Activity is substantial if it is productive mental or physical work.
It is gainful if done for pay or profit. If self-employed, SGA means 40 or more hours of work per month. SSDI benefit levels depend on the earnings of the person on whose social security account the benefit is based, and on the number of persons drawing benefits on the same account. This program is needs based. The Maximum Cash Benefit depends on age, disability, whether an individual or a couple, and living arrangement.