Defamation occurs when a person writes (i.e., libel) or orally states (i.e., slander) a false statement about another person that causes injury to his reputation in the community. The law provides private persons with monetary and injunctive relief when his reputation has been damaged through the willfullness or negligence of another. In order to win a defamation case a plaintiff must prove three elements to the court.
Prove that the defendant made a defamatory statement about the plaintiff. A defamatory statement is one that damages a plaintiff's reputation for good character. Some statements are so defamatory (e.g., Tim is a pedophile) that the plaintiff does not have to prove harm to his reputation; it is considered "defamation per se." Otherwise, a plaintiff will have to explain how his reputation has suffered as a result of defendant's statement. The defendant will have an opportunity to rebut the plaintiff's argument by submitting evidence that the plaintiff already had a poor reputation or that the statement is true.
Prove that the defendant published the defamatory statement about the plaintiff. The publishing requirement is met by the defamatory statement being spoken to third-party (i.e., not the plaintiff) and does not require publishment in mass media. If, however, the defamatory statement appears in a newspaper, magazine or on social media outlets proving this element will be easy.
Prove that the defendant knew that the defamatory statement was false. The law does not protect defendants who willfully harm the reputation of another. Such clear cut cases of defamation are rare in litigation and a more likely scenario is when a defendant should have known that a defamatory statement. For example, a court will not shield a reporter from defamation liability where it is proven that had she conducted due diligence her research would have revealed the defamatory statement to be false. Courts consider failure to conduct due diligence to be a form of negligence.