3-16. Staffs provide commanders and subordinates information relevant to their operational environment and the progress of operations. They use operational variables (political, military, economic, social, information, infrastructure, physical environment, and time—known as PMESII-PT) and mission variables (mission, enemy, terrain and weather, troops and support available, time available and civil considerations— known as METT-TC) as major subject categories to group relevant information. (See FM 6-0 for discussion of the operational and mission variables.)