Computer Matching and Data Sharing Between Agencies

Agencies began comparing computer files in the 1970s, for example matching welfare rolls against payroll records to find fraud. The Computer Matching and Privacy Protection Act of 1988 amended the Privacy Act to regulate such programs. Agencies must sign written matching agreements, have them approved by data integrity boards, publish notices, and verify any match and give the person notice and a chance to respond before cutting off benefits.

Matching is now routine. The Social Security Administration shares death records and earnings data with other agencies, the Treasury's Do Not Pay system screens payments, and states check benefit applicants against federal wage and immigration records. Homeland Security's SAVE system lets agencies check a person's immigration status, and E-Verify lets employers check work eligibility. Supporters say matching saves billions of dollars and prevents fraud.

In 2025 Homeland Security expanded SAVE by linking it to Social Security data so states could check whether registered voters are citizens, and agencies agreed to share IRS and Medicaid records with immigration authorities. The Justice Department sued about 30 states and D.C. that refused to hand over full voter rolls, and by August 2026 courts had ruled against it in 22 of those cases. In September 2026 a federal appeals court upheld an order blocking the IRS from sharing taxpayer addresses with ICE. Supporters say the efforts enforce the law and protect elections, while critics say they violate privacy laws and can flag eligible people by mistake.