Administers the provision of Social Security retirement, survivors and disability benefits to eligible persons, as well as Supplemental Security Income and some aspects of the Medicare program. Also administers the assignment of Social Security numbers, changes in records, and processing of reports of lost or stolen checks. Individual Social Security offices are responsible for applicants who live within their service area, and all services are carried out at the local level. Clients are encouraged to go to the office which serves their Zip Code, though this is not mandatory.