Customs and Border Protection (CBP), within the Department of Homeland Security (DHS), is tasked with securing America's borders and promoting legitimate trade and travel. Within CBP, the U.S. Border Patrol (Border Patrol) is charged with securing the border between ports of entry. Their efforts to develop a measure for this have created a continual evolution of metrics. Border security can be assessed at both the strategic and operational levels. At the operational level, Border Patrol uses the identification of risk and the estimation of its magnitude in its day-to-day operations to secure the border. Understanding the security risks at the border and developing methods to measure the performance of the Border Patrol in allaying these risks are fundamental to congressional oversight of the Border Patrol, CBP, and DHS more broadly. Next, the report summarizes DHS's, and the former Immigration and Naturalization Service's (INS's), use of metrics since the early 2000s. Performance Metrics9

DHS's, and the former INS's, efforts in developing different performance metrics at the strategic level to depict the state of the border have resulted in an array of measures that focus either on border security as a whole or on a component of it ( Figure 1 ). While DHS has shown intent to continually improve its measurement of border security, this new metric is subject to influence by external factors that are outside of the control of DHS and may not directly measure border security. These measures, though subject to limitations, are meant to estimate the Border Patrol's effectiveness in apprehending migrants and deterring migrants from re-entering the United States. Technology

In addition to estimating the level of unauthorized entry of migrants into the United States, DHS has also begun to turn its attention to evaluating the performance of the technology used to secure the border. Other Metrics42

At the strategic level, DHS has used two other performance metrics: the percentage of people apprehended multiple times along the Southwest border, or the recidivism rate (introduced in 2013), and the rate of interdiction effectiveness along the Southwest border between ports of entry, or the effectiveness rate (introduced in 2014). The Border Patrol stated that this metric is "used to determine the effectiveness of border security operation at the tactical—or zone—level but can also affect strategic decisionmaking," such as evaluating whether it is employing the appropriate mix and placement of personnel and assets and whether they are being deployed efficiently and effectively. Optimum deterrence was defined as "the level at which applying more Border Patrol agents and resources would not yield a significant gain in arrests/deterrence." Operational control describes the number of border miles where the Border Patrol can detect, identify, respond to, and interdict cross-border unauthorized activity. After 2010, DHS ceased to use operational control as a metric because the Border Patrol station and sector chiefs could not accurately and reliably use its coding scheme to assess different border regions and the agency did not view it as useful for evaluating border security on a mile-by-mile basis. From 2011 to 2013, DHS used apprehensions as a performance metric for border security in annual performance reports. Operational Metrics80

At the operational level, the Border Patrol estimates risk at the border through the use of risk assessments. These assessments are not used as metrics themselves. However, the Border Patrol's methodology for risk assessments monitors certain metrics, along with other information, in order to estimate the level of risk at the sector level. In addition, other metrics the Border Patrol uses are the recidivist rate and the effectiveness rate, the same metrics that DHS uses as performance metrics. Select Issues for Congress to Consider

In reviewing current metrics and those under development, Congress may consider whether these metrics adequately measure border security. For example, is DHS's new metric in development, unauthorized entry of migrants into the United States, satisfactory or will additional metrics be needed to sufficiently measure border security? Congress may want to consider what type of review and oversight should be required with respect to measurement of performance. Congress may also be interested in the implementation of metrics at operational and strategic levels and how they interact with one another. Therefore, Congress may also consider whether DHS's metrics account for the actions of transit countries and whether DHS is capturing the correct data. For example, a decrease in apprehensions at the Southwest border may not be only a result of successful deterrence by the Border Patrol, it may also be the result of increased apprehensions of unauthorized migrants in Mexico, who are therefore prevented from reaching the U.S. border. New data and methodologies also allow for inclusion of metrics that may be able to provide a more complete or holistic view of border security.
Understanding the risks present at the U.S. borders and developing methods to measure border security are key challenges for the Department of Homeland Security (DHS) and the U.S. Border Patrol, the agency within DHS charged with securing the border between ports of entry. Metrics for border security are used at both the strategic level, by DHS, and at the operational level by Customs and Border Protection (Border Patrol). This report reviews DHS's and the Border Patrol's use of metrics in evaluating their objective to secure the border between ports of entry. DHS and the Border Patrol can use metrics to measure their performance and estimate risks at the border. Additionally, metrics provide Congress with an understanding of DHS's and Border Patrol's progress in securing the border.
At a strategic level, DHS uses performance metrics to understand its ability to meet border security objectives. However, DHS has struggled to create a comprehensive measure of border security. Most recently, DHS has labored to create a new generation of performance metrics, through the estimation of unauthorized entry of migrants into the United States. This measure represents the volume of migration entering the United States and can be influenced by factors outside of DHS's control, and therefore may not directly speak on border security. Congress may want to consider whether this is an adequate performance metric for border security and whether additional and/or more comprehensive and targeted metrics are required.
DHS's Annual Performance Report for FY2014-FY2016 reported two other performance metrics used to measure its progress in securing the border. First, the percentage of people apprehended multiple times along the Southwest border, or the recidivism rate, is used to capture the ability of the Border Patrol to deter migrants from re-entering the United States. Second, the rate of interdiction effectiveness along the Southwest border between ports of entry, or the effectiveness rate, measures the Border Patrol's ability to apprehend unauthorized migrants.
In the past, DHS has used several different performance metrics. For example, from 2001 to 2004, DHS, and the former Immigration and Naturalization Service (INS), used optimum deterrence as a measure for border security, defining it as the level where applying more border security would not significantly increase apprehensions or deterrence. In 2005, DHS began to use operational control as a new measure, describing it as the miles along the border where the Border Patrol had the ability to detect, identify, respond to, and interdict cross-border unauthorized activity. When operational control was retired as a metric, migrant apprehensions became the interim measure for border security from 2011 to 2013.
At an operational level, the Border Patrol uses metrics within its risk assessments. The estimation of risk at the sector level assists the Border Patrol in making day-to-day decisions with regard to how to best align its resources against different threats. The agency determines risk through its "State of the Border Risk Methodology." A secured border is characterized as low risk. The Border Patrol's methodology estimates the magnitude of risk by gathering and understanding intelligence information, developing a detailed awareness of threats at the border, and applying a standardized measurement of risk. These assessments are not used as metrics themselves. However, the Border Patrol's methodology monitors certain metrics at the sector level, such as the recidivist rate and effectiveness rate, which may be able to speak to the Border Patrol's performance.
Metrics can provide an understanding of the state of the border. In reviewing border security metrics, Congress may be interested in issues surrounding the oversight of DHS's measurement practices, the determination of acceptable levels of risk for each metric, and the implementation of strategic and operational metrics and how they relate to one another. Moreover, Congress may consider how metrics can be used to inform decisions on expenditures and whether additional data and methodologies are needed to provide a more holistic view of border issues. Lastly, with migrant demographics shifting and some transit countries conducting their own enforcement of unauthorized migration, Congress may consider how these practices affect data and outcomes and what can be done to account for these changes.