1-52. Operational and mission variables are categories of relevant information commanders and staffs use to help build their situational understanding. Commanders and staffs use the eight interrelated operational variables—political, military, economic, social, information, infrastructure, physical environment, and time (known as PMESII-PT)—to help understand an OE. Operational variables are those aspects of an OE, both military and nonmilitary, that may differ from one operational area to another and affect operations.