From
The Hill:
... SSA mailed outreach letters to individuals informing them of potential
eligibility for Supplemental Security Income (SSI), a program that
provides modest cash benefits and access to Medicaid for low-income
disabled and elderly individuals. Sen. Ron Wyden (D-Ore.) forcefully pushed for the outreach during a Senate Finance hearing in 2021.
Wyden’s push and SSA’s actions did much to help impoverished disabled
and elderly citizens, with SSA indicating the outreach will increase
lifetime SSI payments to these individuals by about $530 million.
The cost of the outreach totaled $32 million,
implying the ratio of benefits received by the public to the cost of
the outreach is 17 to 1. Mailing informational letters, part of SSA’s
Equity and Outreach initiatives, proved to be a highly efficient mechanism to help individuals in poverty. ...
SSA’s outreach was targeted to Social Security beneficiaries who had
very low Social Security benefit amounts and, therefore, might qualify
for some SSI benefits. ...
Here's a link to Social Security's report on this project.