frequently backfires:

Federal investigators have told lawmakers they have evidence that USIS, the contractor that screened Edward Snowden for his top-secret clearance, repeatedly misled the government about the thoroughness of its background checks, according to people familiar with the matter.

The alleged transgressions are so serious that a federal watchdog indicated he plans to recommend that the Office of Personnel Management, which oversees most background checks, end ties with USIS unless it can show it is performing responsibly, the people said.

Cutting off USIS could present a major logistical quagmire for the nation’s already-jammed security clearance process. The federal government relies heavily on contractors to approve workers for some of its most sensitive jobs in defense and intelligence. Falls Church-based USIS is the largest single private provider for government background checks.

The inspector general of OPM, working with the Justice Department, is examining whether USIS failed to meet a contractual obligation that it would conduct reviews of all background checks the company performed on behalf of government agencies, the people familiar with the matter said, speaking on the condition of anonymity because the investigation has not yet been resolved.

After conducting an initial background check of a candidate for employment, USIS was required to perform a second review to make sure no important details had been missed. From 2008 through 2011, USIS allegedly skipped this second review in up to 50 percent of the cases. But it conveyed to federal officials that these reviews had, in fact, been performed.

The shortcut made it appear that USIS was more efficient than it actually was and may have triggered incentive awards for the company, the people briefed on the matter said. Investigators, who have briefed lawmakers on the allegations, think the strategy may have originated with senior executives, the people said.