When discussing hiring, firing or promotion decisions, make sure you can back up any claims with some proof. And impress upon others involved in such discussions to also be truthful and factual, or they could face a defamation lawsuit.
Reason: Under state defamation laws, you can be sued for libel or slander if you make false and defamatory statements during investigations. And that liability can be personal, hitting your pocketbook as well as the organization's.
Always make sure you have proof. Defamation requires making a false statement or claim. The truth is always a defense.
Recent case: When university instructor Karen Overall applied for a tenure position, the university interviewed other professors. One professor told the hiring committee that he believed Overall had represented herself as holding a Ph.D. long before she truly earned one. He also claimed that Overall misused grant money and lied about whether her publications were peer-reviewed.
Overall sued the professor, alleging defamation because those claims weren't true. The trial court dismissed her defamation case, but the 3rd Circuit reinstated it, saying that no immunity exists for statements made to internal employer committees. People making false statements to such committees can be sued for defamation.
The result would have been different if the professor had made the allegations in court or at a government administrative hearing (say, during a EEOC investigation). In that case, he would have had immunity from a lawsuit by Overall. (Overall v. University of Pennsylvania, No. 04-1090, 3rd Cir., 2005)