LOS ANGELES – Criminal background checks conducted on prospective employees routinely contain errors, mismatch people or misclassify criminal offenses, according to a report by the National Consumer Law Center.

The report, released Wednesday, said that since the Sept. 11, 2001, terrorist attacks, employers increasingly have conducted background checks on prospective hires.

That has created a booming industry of Internet companies that cull public information databases for employers. But the information produced by some of those firms is riddled with errors, the report says.

“Background screening companies routinely cut corners to improve their profits and then they wipe their hands of any responsibility for producing an inaccurate or misleading report that can cost a worker his or her job,” wrote Persis Yu, the report’s co-author.

According to the National Consumer Law Center, one man was allegedly denied a job after a prospective employer ran a background check that returned a 1987 rape conviction. But the man, Samuel M. Jackson, was only 4 years old in 1987. The rape conviction was for a man named Samuel L. Jackson, who was incarcerated at the time the check was run.

Situations like Jackson’s have become much more common as more background checks are performed, the report found.

Background checks sometimes contain sealed or expunged information or omit information on how a case was resolved. A job applicant who was arrested, for example, may have been found innocent. But that outcome may not be contained in the information supplied to the employer.