WASHINGTON, Aug. 7 - The federal government has been pouring hundreds of millions of dollars into the once-obscure science called biometrics, producing some successes but also fumbles in a campaign intended to track foreigners visiting the country and the activities of some Americans.
Hoping to block the entry of criminals and terrorists into the United States and to improve the enforcement of immigration laws, government officials have in the past several years created enormous new repositories of digitally recorded biometric data - including fingerprints and facial characteristics - that can be used to identify more than 45 million foreigners. Federal agencies have also assembled data on more than 70 million Americans in an effort to speed law-abiding travelers through checkpoints and to search for domestic terrorists.
The immigration control and antiterrorism campaign was spurred by the Sept. 11 attacks and subsequent Congressional mandates to improve the nation's security. But the effort has fallen far short of its goals, provoking criticism that the government is committed to a technological solution so ambitious that it will either never work or be achieved only at an unacceptably high price.
"I am not satisfied," said Representative Dan Lungren, Republican of California, who is chairman of a House panel that helps oversee the effort. "We are stumbling toward progress. I would hope we would be sprinting."
In defending its record, the Department of Homeland Security points to arrests along the nation's borders. In the past year, thanks to a new system that allows Border Patrol agents to check quickly and comprehensively the fingerprints of every illegal immigrant detained near the border, officers have identified 437 people wanted, previously charged or convicted of homicide; 579 who had sexual assault records and more than 18,000 others with records involving robberies, drugs, kidnappings or assaults.
The State Department said new facial recognition software had also uncovered visa fraud. The software identified 5,731 applicants to the annual visa lottery program who had doctored their names or otherwise cheated. They included people who each submitted at least a dozen applications and tried to disguise themselves with different hairstyles, glasses or expressions.
But the biometric effort still has a long way to go. The State Department, for example, recently started to test so-called electronic passports that contain a small computer chip that holds a digital photograph of the owner. [The department announced on Tuesday that it would begin issuing the electronic passports in December.] But even with the chip, officials at entry points will only have a bigger photograph to compare with the person seeking entry instead of a computer-based biometric analysis that could determine with certainty whether the passport holder was the legal passport owner.
"When it's all in place, there's still no real additional security or at least it's of marginal value," Representative Christopher Cox, Republican of California, said before he stepped down as chairman of the House Committee on Homeland Security to become the head of the Securities and Exchange Commission.
In all but a few locations, another new program, US-Visit - which has cost $1 billion and could exceed $10 billion - can only record foreigners' arrivals, not their departures, meaning it is far from delivering on its promise of creating an immigration tracking system.
The high cost comes from the extensive computer networks that must be built to tie together the data and make it accessible to United States officials around the world.
"We are still just in the formative stages of this," said Rey Koslowski, a political science professor at the University at Albany and the author of a recent report that questioned whether the program's goals could ever be met. "Now may be the time to scale back the mission."
The science of biometrics relies on unique human characteristics - including fingerprints, facial dimensions or the rings and furrows in the colored tissue of the eye - that can verify a person's identity. The government programs that rely on biometrics - at least eight are under way at the Homeland Security and State Departments alone - want to remove the uncertainty involved in using a traditional passport, visa or other identification document.
The enhanced screening starts at the 207 State Department visa processing locations around the world. Since late last year, almost all applicants must be fingerprinted and submit a photograph. The prints are transmitted to Washington, where the Department of Homeland Security compares them to a database of about five million people, mostly criminals, who may be ineligible to receive a visa.
In rural Kentucky, the State Department has put another biometric tool to work. At its visa processing center there, staff members use facial recognition software to compare applicants against a database of digital images of 45 million foreigners - collected from a decade's worth of applications - to see if any had previously applied under a different identity. The screening is being tested on small numbers of applications but will be expanded to all applications starting next year.
Facial recognition systems, which look at skin texture and the facial geography like the distances between the eye sockets or the point of a nose and an eyebrow, are much less accurate than fingerprint-based systems, requiring members of the State Department to examine every reported match.
But the system has been effective, particularly as a fraud-prevention tool in the competition for 50,000 special immigration visas that the State Department offers each year.
The software also spotted the same photograph of a Cambodian child in nine applications with different names, dates of birth and sets of parents.
The screening continues when foreigners come into the country. At domestic security checkpoints, visitors with visas are again fingerprinted and photographed to verify that they are the same people who were given the travel documents. If they are from 27 so-called visa waiver nations - mostly in Europe - they are fingerprinted and photographed for the first time. The federal government uses the data to check against watch lists and to share with law enforcement officials.
Perhaps the most effective effort so far is along the Mexican border, in places like Nogales, Ariz. More than 490,000 people were caught near Nogales last year trying to enter the United States illegally.
Five years ago, the only way to conduct a comprehensive criminal check of fingerprints was to fax the prints to a central processing center, which could take hours.
By last year, all 136 Border Patrol stations were linked to the F.B.I. fingerprint system, which produces results in two minutes.
The checks turned up 113,747 criminal record hits in the last 11 months, or about 7 out of every 50 detainees, compared with 1 in 50 before the new system was installed, a Customs and Border Patrol official said.
"Before, you might have a hunch that some guy was not right, but there was nothing you could do to check further - you just did not have the time," Luke Bilow, a senior patrol agent at Nogales, said.
Among those identified were fugitives that included Francisco Martínez, a Mexican wanted for questioning last year in connection with the killing of his cousin in Florida. Mr. Martínez had fled while the investigation was under way, but turned up at a Border Patrol roadside stop in New Mexico.
The federal government also intends to use biometrics to screen Americans. The State Department has assembled a database of high-resolution digital images of passport applications - including photographs - submitted in the past decade by 70 million Americans.
In conjunction with facial recognition technology, the photos may eventually be used to detect fraudulent passport applications, one State Department official said. Law enforcement officials at the National Counterterrorism Center now have access to the photos for investigations into possible terrorist activity.
At six American airports, A.T.M.-like machines automatically read fingerprints and do eye scans of the irises of passengers enrolled in Registered Traveler, a Homeland Security Department program intended to speed the movement of "trusted travelers," who also had to undergo background checks.
The cost of the program has been modest, $20 million in the last two years. But many critics question its value. Relatively few passengers take part because they must still wait in line to pass through metal detectors and have their bags X-rayed.
At Reagan National Airport outside Washington last Monday morning, one of the busiest times of the week, not a single passenger used the Registered Traveler ID machines for an hour, while hundreds of others passed through the regular checkpoints.
"It offers no benefit to our passengers," Robert Isom, a Northwest Airlines senior vice president, told a House panel in June.
Mr. Isom suggested that officials consider abandoning the program.
Starting this week, the Homeland Security Department is testing a system that automatically tracks people as they cross land borders by issuing visas that transmit radio signals. But critics have pointed out that a person intent on circumventing the system could simply give his visa to someone else to carry across the border, because there is no biometric check.
"If we ever catch a terrorist, we will only catch an extremely dumb terrorist," said a federal official who asked not to be named because he was criticizing the program he was involved in.
Representative Lungren said it was even more disturbing that the State Department accepted as proof of identity for passport applications documents like birth certificates that could easily be forged. In such cases, biometric-based technologies could actually help a smart terrorist.
"What we may have done, in some ways, is give terrorists or criminals tamperproof, fake ID's," he said.But federal officials say patience is required as the biometrics push gets under way.
"These things are tough," said James A. Williams, director of US-Visit. "They take time."
