One exemplary method for message suppression comprises: providing first and second rules, each having one or more preconditions and a conclusion, wherein the first rule also has a suppressed-by attribute and at least one of the second preconditions is suppressing; evaluating the one or more first and second preconditions; identifying the first rule as true or false; displaying the message of the second rule if all of the second preconditions are met; identifying the first rule as suppressed if the second rule is named in the suppressed-by attribute; and inhibiting the message display of the suppressed rule or routing the message to second display. The system can comprise: a database containing knowledge of the production unit; a user interface, and at least one precondition, a suppressed by attribute, and one or more rules each having a conclusion and at least one suppressing precondition; an inference engine; and a display.