News: Stanford GSB

Center for Social Innovation

FOR FURTHER INFORMATION: Helen K. Chang, 650-723-3358, Fax: 650-725-6750

FOR COMMENT contact Perla Ni, 650-724-3629; ni_perla@gsb.stanford.edu

Government Urged to Upgrade Airport Fingerprinting System

July 2005

STANFORD GRADUATE SCHOOL OF BUSINESS—Last autumn Lawrence Wein detected a serious problem in the U.S. government's US-VISIT program, designed to capture terrorists entering American airports by checking their fingerprints. The Stanford Business School professor presented his findings to the White House and the U.S. Department of Homeland Security and testified before two subcommittees of the U.S. House of Representatives Select Committee on Homeland Security. Wein's work sounded alarm bells among politicians and government officials and prompted the government to revisit the design and implementation of the US-VISIT program. In July the government changed its policy.

Wein had cautioned that the system of capturing only two fingerprints from foreign visitors presented a high probability for missing not identifying people—including those on watch lists—when the prints weren't of good quality and urged that the government scan eight or more prints to improve the system. In mid July, Michael Chertoff, secretary for Homeland Security, announced that the government would in the future ask non citizens entering the United States for the first time through the US-VISIT program to complete a 10-fingerscan. The same individuals would be asked for two-print verification during subsequent entries.

Wein raised the concern after analyzing the probabilities of the government's earlier policy. Since the September 11, 2001, attacks on the World Trade Center and the Pentagon, most foreign citizens entering the United States were required to have their fingerprints checked against those of known terrorists. Until the July policy change when non citizens entered through the US-VISIT program, U.S. Customs officials at airports laid each foreign visitor's two index fingers down on a special pad and then waited while the computer compared the images against the fingerprints stored in the system of several million known criminals and suspected terrorists. When the computer detected a match, a person was quietly sequestered for further investigation. While that system is 96 percent accurate overall, Wein found that its performance degraded when fingerprint quality is not good.

Using mathematical models, Wein, along with Manas Baveja, a Ph.D. student at Stanford's Institute for Computational and Mathematical Engineering and a science fellow at the university's Center for International Security and Cooperation, determined that when image quality is poor, accuracy dropped to 53 percent. "About 5 percent of the general public and 10 percent of those on the watch list have bad quality fingerprints due either to genetics or hard labor," Wein says. It's those small percentages that can evade the system—with potentially huge consequences. "We assume that terrorist organizations will eventually defeat the US-VISIT program by employing a majority of people whose fingerprint quality is either naturally bad or deliberately made so," Wein warned.

Wein and Baveja developed various mathematical models that calculated how the system could be tweaked to improve accuracy while not increasing either visitor waiting times at airports or the need for more customs staffing. "We found that instead of scanning two index fingers, scanning eight to ten fingers will result in a 95 percent detection probability, even when fingerprint quality is bad," Wein says.

Wein, the Paul E. Holden Professor of Management Science at the Stanford Graduate School of Business, details his research in an article titled "Using Fingerprint Image Quality to Improve the Identification Performance of the U.S. Visitor and Immigrant Status Indicator Technology Program," co-authored with Baveja. The paper appears in the April 25-29 issue of the Proceedings of the National Academy of Sciences. [Details]

Wein's is one of the first papers produced outside of the U.S. government to be concerned with this important issue. While changing from a two-finger to an eight- or ten-finger system will necessitate expensive new hardware and major disruptions, Wein says the Department of Homeland Security realizes there is a serious vulnerability in its system. Earlier, Wein used mathematical modeling to determine that swift medical treatment, not prevention, is the most effective form of protection against anthrax attacks. That research also attracted the attention of government security agencies, and led to a program whereby the U.S. Postal Service will deliver antibiotics in the Washington, D.C., area in the event of a large anthrax attack.

—Marguerite Rigoglioso

Stanford GSB News

Government Urged to Upgrade Airport Fingerprinting System

Related Links