The Incident Command System (ICS) is a standardized approach to the command, control, and coordination of emergency response that provides a common hierarchy within which responders from multiple agencies can be effective. ICS defines chain of command, management, and operational structures and addresses weaknesses of the past like lack of accountability, poor communication, and an overloaded incident commander. The system establishes common terminology, modular organization, management by objectives, and a unified command structure to coordinate response while maintaining unity of command.