4-16. Mission variables are the categories of specific information needed to conduct operations. The mission variables are mission, enemy, terrain and weather, troops and support available, time available, and civil considerations (known as METT-TC). The purpose of mission variables is to provide a set of information categories focused on what commanders and staffs need to know to achieve situational understanding once assigned a mission. Commanders and staffs use mission variables as a filter to extract information from the operational variables that staffs need to conduct an operation and commanders need to exercise mission command.