A fact is objective, data-based and verifiable. You can check the information and determine if it is true or untrue, whereas you cannot verify an opinion as true or untrue on its own. Knowing the difference is foundational to public affairs and communication strategy practitioners.
Marc Franco demonstrates how to distinguish fact from opinion, especially when opinions are well-reasoned and supported. He discusses how to use evidence to evaluate if a writer presents a weak or strong opinion. He illustrates these important critical thinking skills with several examples. For example, is it fact or opinion when someone says, "the earth is flat"? Although presented as fact, this assertion can be proven false.