2-15. The combined arms training challenge is the same for all echelons of command. The complexity, however, increases at each higher echelon of command. The tempo, scope, and scale of operations at higher command echelons increase coordination requirements for planning and executing staff, joint, multinational, and interagency training. Commanders, at every echelon, focus combined arms training on specific integration and synchronization tasks based on their METL. Figure 2-3 illustrates the scope and scale of the combined arms training challenge.