By working, an individual may demonstrate the ability to engage in SGA, at least for the time worked. However, a finding that work was not SGA during a particular period does not answer the ultimate question of ability to engage in SGA. To answer this question, the DDS must consider all the medical and vocational evidence, of which the work performed after alleged onset of disability is only a part. In some cases, the complete evidence may show that (1) the individual's impairment is less severe than alleged or (2) the person has the physical, mental and vocational qualifications necessary for SGA. Other instructions furnish guides on how to evaluate the total spectrum of medical and vocational evidence for this purpose.

Some onset factors are:

1. 1. 

   Onset of disability cannot be established prior to the end of the last successful engagement in SGA, except in Statutory Blindness cases and cases where there was no SGA for at least 12 months.

2. 2. 

   DDS examiners should be alert to the possible effect of a period of work on the date of disability onset as well as the possibility of establishing a date of onset of disability earlier than the alleged onset date if the evidence would support a medical or medical-vocational allowance at an earlier date in the absence of SGA. In this situation any information in file which indicates that one or more periods of work prior to AOD may have been non-SGA or an unsuccessful work attempt should be developed fully before final determination of the onset date.

When a beneficiary returns to work at the SGA level less than one year after onset, a question is raised as to whether the 12 month duration requirement for disability is met, (see DI 25505.025) and whether the disability should be ceased immediately or continued subject to a trial work period, or whether the prior favorable determination should be reopened and revised to a denial or a later onset date. For a discussion of “Return to Work” issues, refer to DI 13010.105 and DI 13010.110.

Disability ceases when the severity of the physical or mental impairment does not prevent the individual from engaging in substantial gainful activity (SGA) and medical improvement or an exception occurs or, subject to the trial work period (TWP) provisions, the individual demonstrates, by working, the ability to engage in SGA (except in certain title II cases based on statutory blindness or title XVI cases).