This report focuses on “third-party data matching,” i.e., determining people’s eligibility for Medicaid or CHIP by looking at information they have submitted for another purpose. Information about applicants from tax records, the food stamps program, and vital records databases can be used to automate and simplify enrollment and renewal. It can also be used for outreach to those who may not realize they are eligible. Third-party data matching offers the promise of increasing enrollment and retention of eligible children and adults in Medicaid and CHIP, lowering administrative program costs, and improving convenience for applicants.