Which NIMS structure makes cooperative multi-agency decisions?

The answer

The NIMS structure that makes cooperative multi-agency decisions is the MAC Group — the Multiagency Coordination Group, sometimes referred to as a policy group. A MAC Group is typically made up of the agency administrators, executives, or their designees from the organizations involved in or affected by an incident. Because these members carry the authority to commit their agency's resources and money, the MAC Group can make binding, cooperative policy-level decisions on behalf of all participating organizations.

Crucially, a MAC Group does not perform incident command functions and does not replace the Incident Commander. Instead it supports the response by setting overall priorities among competing incidents, resolving conflicts over scarce resources, and providing strategic guidance. It is a decision-making body, not a facility and not a tactical unit.

Why the other options are wrong

• ICS (Incident Command System) manages the tactical, on-scene response through a single Incident Commander and the command/general staff. ICS directs the hands-on operational work; it does not make cooperative multi-agency policy decisions across organizations. Within ICS, Unified Command lets multiple agencies share command of one incident, but that is on-scene tactical command, not the executive policy coordination the question is asking about.
• EOC (Emergency Operations Center) is a physical location — a facility where staff from multiple agencies gather to coordinate information and support the response with resources. An EOC is where coordination happens, but the cooperative executive decision-making role belongs to the MAC Group. (A MAC Group may even meet inside an EOC, but they are distinct concepts.)
• JIS (Joint Information System) handles public information and messaging. Through the Joint Information Center, the JIS ensures coordinated, accurate, timely information reaches the public and stakeholders. It manages communications, not multi-agency policy decisions.

The bigger picture: how the coordination structures fit together

NIMS separates command from coordination on purpose. On the scene, ICS runs the tactical response. Off-scene, three structures support it: the EOC provides a place and staff to marshal resources and share information; the MAC Group provides executive-level policy decisions and priority-setting; and the JIS keeps public messaging unified. Think of the MAC Group as the 'boardroom' that decides which incident gets the last available strike team, the EOC as the 'engine room' that finds and moves that strike team, ICS as the 'field crew' that uses it, and the JIS as the 'press office' that explains it all to the public. Recognizing that only the MAC Group carries delegated executive authority to make cooperative cross-agency policy decisions is exactly what separates the correct answer from the plausible-sounding distractors.