Department of Homeland Security: Continued Actions Needed to Improve Quality of Border Security Metrics Reporting

Summary

What GAO Found The National Defense Authorization Act for Fiscal Year 2017 (2017 NDAA) requires the Department of Homeland Security (DHS) to develop an annual report containing 43 specific metrics to measure the effectiveness of border security. DHS reported on 40 of these metrics in its 2023 Border Security Metrics Report, which it submitted in January 2025. These 40 metrics included two that DHS first included in its 2022 report and one that it first included in its 2023 report. Of the 40 metrics, 21 generally corresponded with their 2017 NDAA definitions, while 19—including the three additional metrics—differed in scope or calculation. GAO previously reviewed DHS's Border Security Metrics Reports in 2019, 2021, and 2023. Six of the recommendations GAO made in these reports remain open. DHS agreed with these recommendations, which highlight an ongoing opportunity for DHS to improve its reporting on border security metrics. Fully addressing these recommendations will help DHS ensure the information it reports is useful to Congress. For example: DHS's Office of Homeland Security Statistics (OHSS)—which is responsible for developing the report—has taken some steps to engage with DHS components, such as by working with the Coast Guard to include two of the newly reported metrics related to maritime threat response. However, OHSS officials have not engaged with components to ensure that certain previously reported metrics—such as those related to illicit drug removal—corresponded with the 2017 NDAA definitions. OHSS officials also have not engaged with Congress on metrics that have been challenging to report, as we previously recommended. By doing so, OHSS could help clarify definitions for these metrics and identify opportunities to refine them. OHSS identified some data limitations in its 2023 Border Security Metrics Report but has not developed a process to systematically review the reliability of data and communicate limitations in its report, as we previously recommended. Such a process would involve OHSS assessing whether the data underlying each of the metrics in the report are reliable and whether any limitations exist that would affect how they are used in the report. Having such a process may help to improve the quality of the metrics in the report and Congress, policymakers, and the public's understanding of the metrics. OHSS has not assessed a statistical model it uses to estimate certain metrics related to unlawful entries into the U.S. since its development in 2016, raising questions about the extent to which the model reflects current southwest border conditions. While OHSS used historical data to account for unavailable survey data in its 2023 Border Security Metrics Report, this modification did not assess whether the inputs to the model or model type remain sufficiently predictive, as we previously recommended. OHSS officials told us they plan to continue using their current statistical model until an alternative model's estimates are valid. Assessing or updating aspects of OHSS's current model could help ensure that it remains predictive and reflects current southwest border conditions. Why GAO Did This Study The U.S. has approximately 6,000 miles of land borders, 95,000 miles of coastline, and more than 300 ports of entry where travelers and cargo are inspected. Securing U.S. border areas is a key part of DHS's mission. Its ability to measure border security activities is essential to managing its responsibilities effectively. The 2017 NDAA requires DHS to report annually on 43 border security metrics. The act also includes a provision for GAO to review and report on DHS's first report and complete biennial reviews for the following 10 years. Since March 2019, we have issued three reports on this topic. This fourth report assesses the extent DHS took steps in its 2023 Border Security Metrics Report to (1) more fully report and increase the usefulness of the metrics reported and (2) improve the quality of the information underlying the metrics reported, as previously recommended. GAO assessed the methodology and data in DHS's report, analyzed DHS's use of statistical models, and interviewed officials from DHS offices and components involved in developing the metrics.