Prior to January 1974, the States made all Medicaid eligibility determinations and
thus were responsible for all accretions and deletions in the Buy-In program.
When the SSI program was implemented in January 1974 the States were given the option
of entering into a “1634 Agreement” with the Social Security Administration (SSA). The 1634 Agreement derives its name
from the section of the Social Security Act that authorizes the Secretary of Health
and Human Services to determine Medicaid eligibility for the aged, blind, or disabled
based upon the beneficiaries’ entitlement to SSI benefits or federally—administered
State supplemental payments.
A number of States entered into 1634 Agreements and as a consequence became automatic
accrete (auto-accrete) States for purposes of State Buy-In. Each month, SSA transmits
data exchange records for SSI beneficiaries to CMS’ Enrollment Database (EDB). Based
upon information contained in the data exchange records, CMS accretes or deletes beneficiaries
to the Buy-In rolls for auto-accrete States.