Because a statement must be false to be defamatory, a statement of opinion cannot form the basis of a defamation claim because it cannot be proven true or false. For example, the statement that Bill is a short-tempered jerk, is clearly a statement of opinion because it cannot be proven to be true or false. Again, courts will look at the context of the statement as well as its substance to determine whether it is opinion or a factual assertion. Adding the words "in my opinion" generally will not be sufficient to transform a factual statement to a protected opinion. For example, there is no legal difference between the following two statements, both of which could be defamatory if false:
"John stole $100 from the corner store last week."
"In my opinion, John stole $100 from the corner store last week."
For more information on the difference between statements of fact and opinion, see the section on Opinion and Fair Comment Privileges.
Defamation Per Se
Some statements of fact are so egregious that they will always be considered defamatory. Such statements are typically referred to as defamation "per se." These types of statements are assumed to harm the plaintiff's reputation, without further need to prove that harm. Statements are defamatory per se where they falsely impute to the plaintiff one or more of the following things:
a criminal offense;
a loathsome disease;
matter incompatible with his business, trade, profession, or office; or
serious sexual misconduct.
See Restatement (2d) of Torts, §§ 570-574. Keep in mind that each state decides what is required to establish defamation and what defenses are available, so you should review your state's specific law in the State Law: Defamation section of this guide for more information.