Those advocates want the government to make sure people know what information prospective employers see, so that errors can be corrected and abusive companies can be held responsible.

Use of criminal-background data is exploding as the economy struggles back from the worst job crisis in decades, the National Consumer Law Center says in the report, which is being released today. To meet surging demand, countless dubious companies have sprouted up, it says.

"It's the Wild West for background-screening report companies," says Persis Yu, lead writer of the report. "They're generating billions in revenue, but they have little or no accountability."

Data providers obtain information from online public records, private vendors, jails and police blotters, it says. Sloppy handling of that data can cause a search on one person to turn up a rap sheet about someone with a similar name, for example.

Other common errors include displaying criminal records that were supposed to be sealed or wiped clean, misclassifying minor offenses as major crimes and listing charges that have been dismissed.