Securing U.S. border areas, including approximately 6,000 miles of land borders and 95,000 miles of coastline, is a key part of the Department of Homeland Security’s (DHS) mission. Its ability to measure border security activities is essential to managing its responsibilities effectively. The Government Accountability Office (GAO) released its report reviewing how DHS measures border security activities: Department of Homeland Security: Continued Actions Needed to Improve Quality of Border Security Metrics Reporting (GAO-26-108715).
Questions
- What laws were the basis of GAO’s review and what key agencies were involved?
The National Defense Authorization Act for Fiscal Year 2017 (2017 NDAA) requires DHS to develop an annual Border Security Metrics Report containing 43 border security metrics defined in the law. The 2017 NDAA also requires us to review the data and methodology in DHS’s report on a recurring basis, including determining whether DHS reported the metrics as defined in the law. The 43 metrics outlined in the 2017 NDAA measure key border security activities, such as the number of apprehensions and an illegal drug removal rate. To report these metrics, DHS uses data from several of its components, including the U.S. Coast Guard and U.S. Customs and Border Protection. For example, DHS collects data from the Coast Guard to measure the ratio of illegal drugs removed or abandoned at sea for one fiscal year compared to the average amount in the five prior years.
2. What are the most important takeaways from GAO’s review?
In our review of DHS’s Fiscal Year 2023 Border Security Metrics Report, which DHS submitted to Congress in January 2025, we found that the department reported on all but three of the 43 required metrics. Additionally, we found that just over half (21) of the 40 metrics DHS reported on generally corresponded with the definitions in the 2017 NDAA. However, 19 of the 40 metrics differed in scope or in how the department calculated data for metrics that were rates or estimates from their 2017 NDAA definitions. For example, for one part of a metric on maritime threats, DHS only reported Coast Guard data while the law requires data from other DHS components as well.
We also found that DHS has not assessed or updated a statistical model it uses for estimating certain metrics involving unlawful entries into the U.S since developing it in 2016. In a prior review, we recommended that DHS assess its statistical model and use the results to update or inform its efforts to replace the model. DHS has not yet taken these steps and has not determined whether it can use a different model to estimate the metrics. Assessing the model and updating or replacing it as needed could help ensure that it still accurately predicts current conditions along the southwest border, such as the characteristics of those crossing the border unlawfully.
3. If GAO identified any areas for improvement with the report reviewed, how persistent have these been, and how have they changed over time (if at all)?
We previously reviewed DHS’s Border Security Metrics Report three times (in 2019, 2021, and 2023) and consistently found that (1) DHS has not reported all metrics as defined by the law and (2) that DHS could improve the quality of the information in the report.
Since we first reviewed DHS’s report in 2019, the department increased the number of metrics for which it reported information from 35 to 40. Consistent with what we found in our latest review of DHS’s Border Security Metrics Report, we found in our other three reviews that roughly half of the metrics reported corresponded to their 2017 NDAA definitions. The other half differed in scope or in the way DHS calculated data for metrics that were rates or estimates.
Our four reviews also highlighted that DHS could improve the quality of the information in its reports by systematically assessing data reliability and communicating relevant limitations. The department has reported some limitations in its reports, but not others. For example, we found that for two metrics related to maritime threats that DHS developed using Coast Guard data, DHS’s report to Congress does not explain that the number of drug interdictions reported for a given year may change if the underlying data change. For instance, the number of drug interdictions credited to the Coast Guard—and therefore included in DHS’s report—could change if a different agency is subsequently credited with an interdiction. Assessing data reliability in its Border Security Metrics Report and fully reporting relevant limitations could help DHS assure Congress has a better understanding and appropriate interpretation of the data in the report.
4. What recommendations has GAO made and how, if at all, has the agency addressed them?
Across our four reviews of DHS’s Border Security Metrics Report, we have made eight recommendations to help the department improve the quality and usefulness of the information it reports to Congress. DHS has addressed two of our recommendations by reporting additional information on the statistical model it uses. However, DHS has not yet addressed our other six recommendations for improving the comprehensiveness and quality of information in DHS’s report. For example:
- To help ensure that the metrics DHS reports fully correspond to the definitions in the law, we recommended that the department engage with components to more comprehensively report the metrics as defined by the 2017 NDAA in its Border Security Metrics Report. While DHS has engaged with components to increase the number of metrics for which it reported information, DHS has not engaged with components to ensure that certain previously reported metrics corresponded with the 2017 NDAA definitions.
- To help improve the quality of the information in DHS’s report, we also recommended that DHS develop and implement a process to systematically review the reliability of data and communicate relevant limitations in its report to Congress. DHS officials stated that they could implement a more robust process for reviewing the reliability of the data potentially starting with the 2025 Border Security Metrics Report.
Securing U.S. borders is a complex undertaking and a key part of DHS’s mission for which DHS has made significant investments over the years. Fully implementing the six open recommendations can help ensure that Congress has quality information to understand the effectiveness of those investments.
