Department of Homeland Security's FY 2021 Compliance with the Payment Integrity Information Act of 2019 and Executive Order 13520, Reducing Improper Payments [open pdf - 4MB]
From the Highlights: "Our objective was to determine whether DHS complied with PIIA [Payment Integrity Information Act of 2019] and Executive Order 13520, 'Reducing Improper Payments' (November 20, 2009), in fiscal year 2021. We also evaluated the accuracy and completeness of DHS' payment integrity reporting. [...] We made two recommendations that, when implemented, should improve DHS' compliance with PIIA."
Department of Homeland Security, Office of Inspector General, Report No. OIG-22-45
U.S. Department of Homeland Security, Office of the Inspector General: https://www.oig.dhs.gov/