Fingerprint checks are no longer just for criminal suspects or passport applicants. Schools, youth sports teams, volunteer groups and resorts are requiring volunteers who work with children to get fingerprinted.
At the same time, the fast-growing ride-sharing service Uber is fighting the use of fingerprinting of its drivers in several states, saying the checks are both unreliable and biased.
Even though fingerprinting has been used by law enforcement agencies to identify lawbreakers for more than a century, what's new is its use to weed out possible child molesters or those with criminal records ahead of time.
"People are taking security a lot more seriously," said Anil Jain, distinguished professor of computer science at Michigan State University and an expert in fingerprint identification technology. "If you have someone with a prior criminal record, do you want them working with the kids?"
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Pennsylvania, California, Michigan and other states have passed new laws requiring fingerprinting for school volunteers, spurred by molestation scandals at local schools and universities like Penn State. At the same time, the big boom in fingerprint checks is raising questions about its accuracy and how well fingerprint capture machines work.
Maryland's legislature passed a law last year requiring ride-sharing drivers to get fingerprint checks, just like bus and taxi drivers. But Uber protested, and the state's Public Service Commission backed down after Uber threatened to leave the state.
In making its decision, the PSC said that "neither fingerprinting-based nor commercial background checks are completely comprehensive and accurate."
The PSC allowed Uber to conduct its own background checks to verify that its drivers don't have a criminal past. Uber drivers in New York City must get fingerprinted, but the company pulled out of Austin, Texas, in 2016 after city officials imposed a requirement there. Chicago and Houston are considering fingerprinting Uber drivers as well.
An Uber spokesperson said the company uses existing criminal, motor vehicle and terrorist suspect databases to check that applicants have a clean record. It also uses a document verification company to authenticate documents presented by applicants.
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Uber CEO Travis Kalanick said at a conference in June 2016 that Uber's opposition to fingerprinting has more to do with justice for people who have been unfairly snared in the U.S. criminal justice system. By using other background check methods, Uber says it gives people who have been arrested the ability to work as drivers.
"Imagine a country where people might get arrested who shouldn't get arrested. Imagine if that country were the U.S.," Kalanick said. "We have systems in place where if you're arrested, you literally can't get work, even if you're found to be innocent. And it's unjust."
Uber argues that the FBI's fingerprint database, known as Next Generation Identification (NGI), is biased because only half of its arrest records include the final disposition of the person's case.
Critics say that Uber needs to use both fingerprinting and other forms of background checks to find out if drivers are who they say they are, and have a clean record.
Michigan State's Jain has consulted for the Department of Homeland Security on fingerprinting technology as well as advised leaders of India, which has fingerprinted 1 billion of its 1.2 billion residents for government ID cards in the past six years. India got around the privacy problem by only allowing the fingerprint check to verify someone's identity that they showed up for work, rather than tying the fingerprint to a criminal record.
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Many other countries use biometrics such as fingerprints for national ID cards, but the United States has resisted creating such a national database. In the meantime, Jain says some kind of biometric marker, such as fingerprint, facial recognition or iris scan, is needed to verify a person's ID.
"That is the only way to do it," Jain said. "Otherwise, you could be giving a false name. That's why a biometric is more reliable than using our name and address."
In the United States, Jain says only a tiny number of people are unable to record their fingerprints.
"It depends on the skill of the operator and the condition of the finger and the weather and whether your skin is too dry," Jain said.
Bricklayers, welders and hotel cleaning workers who handle chemicals often are unable to give fingerprints, he said, although there is no evidence that any ethnic groups are more likely to "fail" a fingerprint test.
These tests cost anywhere from $20 to $50 and use an optical scanner to take digital images of the tiny ridges, valleys and swirls that comprise a person's fingerprint.
Elham Tabassi is a researcher at the National Institute of Standards and Technology in Gaithersburg, Md., who tests the algorithms inside commercial fingerprint machines. With the explosion of new laws requiring fingerprints for work and volunteer agencies, the agency is putting together new standards on how the machine decides if the person's print has been accurately captured.
"Studies say that for fingerprints, only 1 or 1.5 percent are not useful," Tabassi said. "What we don't know is what quality algorithm is being used in that capture device."
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