SSI

• The onset date, when applying for SSI, is typically the date of application. This date determines the start date of payment. Applicants will typically, after approval, receive retroactive payments back to the date the application was received, Medical evidence is not, in this case, necessary to determine onset, and an exact date of onset need not be determined.
  
  

SSDI

• The onset date, when applying for social security disability benefits, is established based on evidence of disability. Traditionally medical records are used to determine exactly when a medically verifiable disability began, though work history, and personal testimony may also be used as evidence. There is a five month wait period after the established onset date before one becomes eligible for Social Security Disability payments. Applications which are approved for payment will still have this waiting period. The waiting period is solely based on the date of onset.
  
  

Approval

• If an onset date cannot be determined, through the examination of medical records, work history, and personal allegation, then an applicant may be denied benefits. Work history and personal testimony are used only when considering the severity of a condition or the deterioration of health. A medical condition must be verified by medical records for a date of onset to be established. The date of onset cannot occur before the date on which the condition was medically confirmed.
  
  

Waiting Period

• There is a 5 month waiting period after the onset date of a disability, before an applicant becomes eligible for social security disability payment. Application date does not affect this waiting period in any way. This 5 months will be deducted from retroactive payments. There is no such waiting period for SSI payment. The sooner you apply for SSI, the sooner you will become eligible for payment.
  
  

Backpay

• If an adjudicator, typically a judge, determines that the onset date of the disability is more than 5 months prior to the date of application, an applicant may be entitled to retroactive payments. An onset date 17 months or more prior to the application date, may mean the applicant is entitled to payment for the 12 months that would have followed their 5 month wait period. There is a 12 month maximum on retroactive payment. If the application was made more than 17 months after the date of onset, the applicant is still only entitled to 12 months of back pay.