 In the United States, both the Social Security Administration and the Centers for Medicare and Medicaid Services have an Office of the Chief Actuary that deals with Social Security and Medicare, respectively.A similar agency in the United Kingdom is called the Government Actuary's Department (GAD).In the U.S., the Office of the Chief Actuary at the Social Security Administration plans and directs a program of actuarial estimates and analyses relating to SSA-administered retirement, survivors and disability insurance programs and to proposed changes in those programs.