Claims, Arguments, Evidence (CAE) framework is used in safety, security and assurance cases.
Claim. A claim is a true/false statement about a property of a particular object. A claim is just what you might consider it to be from common usage of the term; an idea that someone is trying to convince somebody else is true. An example claim could be made on a train, “The train is safe”.
Argument. An argument is a rule that provides the bridge between what we know or are assuming (sub-claims, evidence) and the claim we are investigating. The argument used depends on the type, trustworthiness and extent of available evidence and the nature of the claim. Note that "argument" is an overloaded word and we are using with a specific meaning here.
Evidence. Evidence is an artefact that establishes facts that can be trusted and lead directly to a claim. In projects there can many sources of information, but what makes this evidence is the support or rebuttal it gives to a claim.