The concept that mandates every individual is assigned to onlyone single supervisoris known asUnity of Command. This is a fundamental principle of theIncident Command System (ICS)and theNational Incident Management System (NIMS). The purpose of Unity of Command is to eliminate confusion caused by conflicting instructions and to ensure a clear, vertical chain of command.

Under Unity of Command, a responder should never receive orders from multiple bosses. If a firefighter is assigned to "Division A," their only supervisor is the "Division A Supervisor." Even if a high-ranking Chief from another district walks by and gives an order, the responder must report back to their single assigned supervisor. This prevents the "freelancing" that often leads to injuries and deaths during high-stress disaster operations.

It is frequently confused withSpan of Control(Option B). Span of Control refers to thenumberof subordinates a supervisor can effectively manage (typically a ratio of 1:5). While Span of Control deals with the "how many," Unity of Command deals with the "who reports to whom."Controlling(Option C) is a general management function but not a specific NIMS technical term for reporting relationships.

For aCEDPprofessional, enforcing Unity of Command is essential for accountability. In large-scale disasters where hundreds of agencies converge, the lack of Unity of Command is the most common cause of organizational failure. By ensuring everyone has exactly one supervisor, the Incident Commander can track the location and safety of every soul on the "fireground" or disaster site through a single, consolidated reporting structure.