Darlene Martinez, 57, believes that a faulty background check cost her a job at a Phoenix hospital, the Arizona Republic reports. She was confused with Darlene Foster Ramirez, who was found guilty in 2009 of dangerous-drug possession. The case highlights questions about the accuracy of background checks, which legal experts say can be filled with errors due to incomplete databases and confused identities. These errors can be difficult to fix, costing applicants job opportunities and disrupting livelihoods.

A background screening services says on its report "that they verified by Social Security and date of birth, both of which we’ve been able to confirm are not matching,” says Martinez' lawyer. “How much does someone have to go through to prove they are not a felon?” The Society for Human Resource Management says that about two-thirds of employers conduct criminal background checks on all job candidates. An array of companies, which don’t have to be licensed, offer the service. Searches vary in accuracy. An April report published by the National Consumer Law Center found that many databases are incomplete or include outdated case information. This summer, the Federal Trade Commission fined California-based HireRight, one of the largest firms in the background-screening field, $2.6 million for failing to use “reasonable procedures to assure the maximum possible accuracy.”