Re: Degree of evidence
A single example is a nonconformity.
However, the decision of how to proceed with this nonconformity relies on various factors, such as the risk of failure introduced or enabled by this single nonconformity. If we were talking about purchase orders for office materials I would look for more than one example before calling for action to resolve. If, however we are referring to an inspection record following a repair to a nuclear station's cooling piping, a single errant document can and arguably should generate an action.