(R) Responsible: Person who performs an action or does the work.
(A) Accountable: Person who is ultimately accountable and has Yes/No/Veto
(C) Consulted: Person that needs to give feedback and contribute to the action before it can be done and signed-off on.
(I) Informed: Person that needs to know about the decision or action but does not need to be formally consulted or contribute to the decision or action.