Editor's note 5 12 17: For unknown reasons, the DHS has taken down the page that we linked to. The link was cited by several other websites, and did exist.

A damning report from the DHS inspector general explains why the Immigration and Customs Enforcement agency has such a difficult time in catching foreigners who overstay their visas.

The problems are tied to incompetent oversight by the DHS Chief Information Officer and the dizzying number of databases that contain information on people who enter the country.

The report concludes:

Department of Homeland Security IT systems did not effectively support ICE visa tracking operations. ICE personnel responsible for investigating in-country visa overstays pieced together information from dozens of systems and databases, some of which were not integrated and did not electronically share information. Despite previous efforts to improve information sharing, the DHS Chief Information Officer (CIO) did not provide the oversight and centralized management needed to address these issues. Additionally, ICE did not ensure that its field personnel received the training and guidance needed to properly use the systems currently available to conduct visa overstay tracking.

Further, the Department lacked a comprehensive biometric exit system at U.S. ports of departure to capture information on nonimmigrant visitors who exit the United States. Without a complete exit system, DHS relied on third-party departure data, such as commercial carrier passenger manifests, to confirm a visitor’s departure from the country. However, these commercial sources occasionally provided false departure or arrival status on visitors.  

The end result was that ICE was able to arrest only a miniscule number of visa overstays:

ICE arrested just 0.4 percent of visa overstays it could account for, according to an audit by the inspector general.

The agency has 27 different databases used to investigate and track immigrants who remain in the country past the deadline issued on their temporary visas. The lack of a cohesive system has "produced numerous inefficiencies," making ICE ineffective at catching visa overstays who may pose security risks, according to the audit.

[...]

Of the more than 500,000 identified overstays, only 3,402 were arrested, which amounts to less than 0.4 percent.

ICE's databases also had inaccurate information recorded on those who were arrested.

"In some cases, the individuals arrested had been reported in DHS systems as having already left the United States," the inspector general said. "Because this information was not recorded, ICE personnel were unable to provide an exact number when asked during our audit."

The United States issued more than 10.8 million nonimmigrant visas in 2015. The inspector general said that although only a small percentage overstay their visas, those individuals could pose severe national security risks.

"For example, two of the 19 hijackers on September 11, 2001, were visa overstays," the inspector general said. "This prompted the 9/11 Commission to call for the government to ensure that all visitors to the United States are tracked on entry and exit."

The report highlights the antiquated computer systems being used by ICE that do not have the capability to link up various data bases that would alert authorities if someone overstays their visa. A "biometric" entry and exit system would go a long way toward addressing the problem. Instead of relying on passenger manifests from the airlines, ICE would have its own data base of those who entered the US and would know almost immediately if someone was in the country illegally. 

The governmet-wide IT problem is present in every agency and every department. The process to upgrade computer systems takes so long that by the time requests are approved, the proposed computer systems are nearly obsolete. You would think something as important to the security and safety of American citizens as a data base that keeps track of foreigners would be a high priority for ICE. 

But apparently, DHS has better uses for IT funds than to upgrade its visa data base computers.