When you’re correcting someone , be prepared to back up your point with real evidence, and not just your well-intended opinion.
Real data that supports your point is the single best way to correct false information.

To be a real team player, offer to help get the things on the right patch.
Lend a hand in repairing a situation will emphasize collaboration over competition and it will make you far more pleasant to work with to boot.

Pull the person you want to correct aside for a private, one-on-one conversation instead of highlighting their error in front of a larger group.
Also, to correct them before they get in trouble for their mistake. A little embarrassment right now will save them even greater mortification in the...