WASHINGTON (AP) -- The system Congress and the Obama administration want employers to use to help curb illegal immigration is failing to catch more than half of the unauthorized workers it checks, a research company has found.
The online tool E-Verify, now used voluntarily by employers, wrongly clears illegal workers about 54 percent of the time, according to Westat, a research company that evaluated the system for the Homeland Security Department. E-Verify missed so many illegal workers mainly because it can't detect identity fraud, Westat said.
"Clearly it means it's not doing its No. 1 job well enough," said Marc Rosenblum, a researcher at the Migration Policy Institute, a nonpartisan Washington think tank.
E-Verify allows employers to run a worker's information against Department of Homeland Security and Social Security databases to check whether the person is permitted to work in the U.S. The Obama administration has made cracking down on employers who hire people here illegally a central part of its immigration enforcement policy, and there are expectations that some Republicans in Congress will try in coming weeks to make E-Verify mandatory.
Much of the criticism of E-Verify has focused on whether U.S. citizens and legal immigrants with permission to work were falsely flagged as illegal workers. Immigration officials have been taking steps to improve such inaccuracies. Westat reported that 93 percent of the cases checked were legal workers who were accurately identified on first try. Another .7 percent were legal workers who initially were rejected.
Homeland Security Secretary Janet Napolitano, testifying in a House hearing on her agency's proposed budget Thursday, said she doubts the 54 percent inaccuracy rate for illegal workers. She said things are being added to the system to root out identity fraud.
"E-Verify is absolutely where we are going in terms of incentivizing employers and making sure we are using a legal work force," Napolitano said.
Sen. Chuck Schumer of New York, who is writing the Democrats' immigration bill and has fought expanding E-Verify because of its flaws, said Wednesday that the fact that E-Verify was inaccurate so often shows that it is not an adequate tool.
"This is a wake-up call to anyone who thinks E-Verify is an effective remedy to stop the hiring of illegal immigrants," Schumer said.
A worker verification process like E-Verify is considered essential for any immigration overhaul proposal to have a chance of approval in Congress.
Westat's report, completed in December using data from 2008, was quietly posted on Homeland Security's Web site Jan. 28 along with a summary that pointed out E-Verify is accurate "almost half of the time."
"While not perfect, it is important to note that E-Verify is much more effective" than the paper forms used by most employers, the summary said.
Rosenblum, who has studied E-Verify, said Westat's evaluation shows it doesn't make sense to substantially expand and invest in E-Verify without fixing the identity theft problem.
Bill Wright, a spokesman for U.S. Citizenship and Immigration Services, said the agency has created an anti-immigrant identity fraud unit in Buffalo, N.Y., to address the issue.
The agency, part of the Homeland Security Department, is developing a way for people to screen themselves through E-Verify so they can show potential employers they can work legally.
About 184,000 of the nation's 7 million to 8 million employers are using E-Verify, according to the Homeland Security Department.
Congress gave DHS about $100 million to spend on E-Verify in its 2010 budget.