Disability Determination Services, commonly called DDS, are state agencies, funded by the United States Federal Government. Their purpose is to make disability findings for the Social Security Administration. Applicants for Social Security Disability Insurance (SSDI) or Supplemental Security Income (SSI) file applications for disability benefits at local Social Security field offices. If the application is accepted it is sent to the DDS in the state where the applicant lives to have a person's claim of disability assessed.