Since fiscal year 2011, DHS has used changes in the number of apprehensions on the southwest border between ports of entry as an interim measure for border security as reported in its annual performance reports. In fiscal year 2011, DHS reported data meeting its goal to secure the land border with a decrease in apprehensions. In addition to collecting data on apprehensions, Border Patrol collects and analyzes various data on the number and types of entrants who illegally cross the southwest border between the ports of entry, including collecting estimates on the total number of identified—or “known”—illegal entries. Border Patrol’s estimate of known illegal entries includes illegal, deportable entrants who were apprehended, in addition to the number of entrants who illegally crossed the border but were not apprehended because they crossed back into Mexico (referred to as turn backs) or continued traveling into the U.S. interior (referred to as got aways). Border Patrol collects these data as an indicator of the potential border threat across locations. Border Patrol data show that apprehensions within each southwest Border Patrol sector decreased from fiscal years 2006 to 2011, generally mirroring the decrease in estimated known illegal entries within each sector. In the Tucson sector, for example, our analysis of Border Patrol data showed that apprehensions decreased by 68 percent from fiscal years 2006 to 2011, compared with a 69 percent decrease in estimated known illegal entries, as shown in figure 1. Border Patrol officials attributed the decrease in apprehensions and estimated known illegal entries from fiscal years 2006 through 2011 within southwest border sectors to multiple factors, including changes in the U.S. economy and successful achievement of its strategic objectives. Border Patrol’s ability to address objectives laid out in the 2004 Strategy was strengthened by increases in personnel and technology, and infrastructure enhancements, according to Border Patrol officials. For example, Tucson sector Border Patrol officials said that the sector increased manpower over the past 5 years through an increase in Border Patrol agents that was augmented by National Guard personnel, and that CBP’s Secure Border Initiative (SBI) provided border fencing and other infrastructure, as well as technology enhancements. Border Patrol officials also attributed decreases in estimated known illegal entries and apprehensions to the deterrence effect of CBP consequence programs— programs intended to deter repeated illegal border crossings by ensuring the most efficient consequence or penalty for individuals who illegally enter the United States. Data reported by Border Patrol following the issuance of our December 2012 report show that total apprehensions across the southwest border increased from over 327,000 in fiscal year 2011 to about 357,000 in fiscal year 2012. It is too early to assess whether this increase indicates a change in the trend for Border Patrol apprehensions across the southwest border. Border Patrol collects other types of data that are used by sector management to help inform assessment of its efforts to secure the border against the threats of illegal migration, smuggling of drugs and other contraband, and terrorism. These data show changes, for example, in the (1) percentage of estimated known illegal entrants who are apprehended, (2) percentage of estimated known illegal entrants who are apprehended more than once (repeat offenders), and (3) number of seizures of drugs and other contraband. Border Patrol officials at sectors we visited, and our review of fiscal years 2010 and 2012 sector operational assessments, indicated that sectors have historically used these types of data to inform tactical deployment of personnel and technology to address cross-border threats; however, the agency has not analyzed these data at the national level to inform strategic decision making, according to Border Patrol headquarters officials. These officials stated that greater use of these data in assessing border security at the national level may occur as the agency transitions to the new strategic plan. Apprehensions compared with estimated known illegal entries. Our analysis of Border Patrol data showed that the percentage of estimated known illegal entrants who were apprehended by the Border Patrol over the past 5 fiscal years varied across southwest border sectors. The Tucson sector, for example, showed little change in the percentage of estimated known illegal entrants who were apprehended by Border Patrol over the past 5 fiscal years. Specifically, our analysis showed that of the total number of estimated known aliens who illegally crossed the Tucson sector border from Mexico each year, Border Patrol apprehended 62 percent in fiscal year 2006 compared with 64 percent in fiscal year 2011, an increase of about 2 percentage points. Border Patrol headquarters officials said that the percentage of estimated known illegal entrants who are apprehended is primarily used to determine the effectiveness of border security operations at the tactical—or zone—level but can also affect strategic decision making. The data are also used to inform overall situational awareness at the border, which directly supports field planning and redeployment of resources. Repeat offenders. Changes in the percentage of persons apprehended who have repeatedly crossed the border illegally (referred to as the recidivism rate) is a factor that Border Patrol considers in assessing its ability to deter individuals from attempting to illegally cross the border. Our analysis of Border Patrol apprehension data showed that the recidivism rate has declined across the southwest border by about 6 percentage points from fiscal years 2008 to 2011 in regard to the number of apprehended aliens who had repeatedly crossed the border in the prior 3 years. Specifically, our analysis showed that the recidivism rate across the overall southwest border was about 42 percent in fiscal year 2008 compared with about 36 percent in fiscal year 2011. The Tucson sector had the third-highest recidivism rate across the southwest border in fiscal year 2011, while the highest rate of recidivism occurred in El Centro sector, as shown in figure 2. According to Border Patrol headquarters officials, the agency has implemented various initiatives designed to address recidivism through increased prosecution of individuals apprehended for crossing the border illegally. Seizures of drugs and other contraband. Border Patrol headquarters officials said that data regarding seizures of drugs and other contraband are good indicators of the effectiveness of targeted enforcement operations, and are used to identify trends in the smuggling threat and as indicators of overall cross-border illegal activity, in addition to potential gaps in border coverage, risk, and enforcement operations. However, these officials stated that these data are not used as a performance measure for overall border security because while the agency has a mission to secure the border against the smuggling threat, most smuggling is related to illegal drugs, and that drug smuggling is the primary responsibility of other federal agencies, such as the Drug Enforcement Administration and U.S. Immigration and Customs Enforcement, Homeland Security Investigations. Our analysis of Border Patrol data indicated that across southwest border sectors, seizures of drugs and other contraband increased 83 percent from fiscal years 2006 to 2011, with drug seizures accounting for the vast majority of all contraband seizures. Specifically, the number of drug and contraband seizures increased from 10,321 in fiscal year 2006 to 18,898 in fiscal year 2011. Most seizures of drugs and other contraband occurred in the Tucson sector, with about 28 percent, or 5,299, of the 18,898 southwest border seizures occurring in the sector in fiscal year 2011 as shown in figure 3. Data reported by Border Patrol following the issuance of our December 2012 report show that seizures of drugs and other contraband across the southwest border decreased from 18,898 in fiscal year 2011 to 17,891 in fiscal year 2012. It is too early to assess whether this decrease indicates a change in the trend for Border Patrol seizures across the southwest border. Southwest border sectors scheduled most agent workdays for enforcement activities during fiscal years 2006 to 2011, and the activity related to patrolling the border accounted for a greater proportion of enforcement activity workdays than any of the other activities. Sectors schedule agent workdays across various activities categorized as enforcement or nonenforcement. Across enforcement activities, our analysis of Border Patrol data showed that all sectors scheduled more agent workdays for “patrolling the border”—activities defined to occur within 25 miles of the border—than any other enforcement activity, as shown in figure 4. Border Patrol duties under this activity include patrolling by vehicle, horse, and bike; patrolling with canines; performing sign cutting; and performing special activities such as mobile search and rescue. Other enforcement activities to which Border Patrol scheduled agent workdays included conducting checkpoint duties, developing intelligence, and performing aircraft operations. Border Patrol sectors and stations track changes in their overall effectiveness as a tool to determine if the appropriate mix and placement of personnel and assets are being deployed and used effectively and efficiently, according to officials from Border Patrol headquarters. Border Patrol calculates an overall effectiveness rate using a formula in which it adds the number of apprehensions and turn backs in a specific sector and divides this total by the total estimated known illegal entries— determined by adding the number of apprehensions, turn backs, and got aways for the sector. Border Patrol sectors and stations report this overall effectiveness rate to headquarters. Border Patrol views its border security efforts as increasing in effectiveness if the number of turn backs as a percentage of estimated known illegal entries has increased and the number of got aways as a percentage of estimated known illegal entries has decreased. Border Patrol data showed that the effectiveness rate for eight of the nine sectors on the southwest border increased from fiscal years 2006 through 2011. For example, our analysis of Tucson sector apprehension, turn back, and got away data from fiscal years 2006 through 2011 showed that while Tucson sector apprehensions remained fairly constant at about 60 percent of estimated known illegal entries, the percentage of reported turn backs increased from about 5 percent to about 23 percent, while the percentage of reported got aways decreased from about 33 percent to about 13 percent, as shown in figure 5. As a result of these changes in the mix of turn backs and got aways, Border Patrol data showed that enforcement effort, or the overall effectiveness rate for Tucson sector, improved 20 percentage points from fiscal year 2006 to fiscal year 2011, from 67 percent to 87 percent.