He could find no evidence to back up her claims.

He did not offer any evidence to back up his claim.

Not that he has any hard data to back up his claim.

Williams used data from the federal government to back up his claim.

Could you provide some statistics to back up your claim?

"She's basically using my research to back up her own claim."

He called upon the newcomers to back up his claim.

"Shall we see who has the power to back up their claims?"

But he declined to give any figures to back up his claim.

But without any actual career to back up her claim on the public, the question becomes: why did we watch?