The Casualty Classification is a way to classify the status of UNSC Army, Navy, Air force, and Marine soldiers.
- KIA Killed In Action. This term is used when a soldier is killed during battle, or deaths resulting from a war.
MIA - Missing In Action. This term is used when the status of a soldier is unknown, whether they are dead, wounded, or simply lost.
- POW Prisoner Of War. This term is used for soldiers who are captured as part of a war. A medal is awarded to any soldier who is captured for any length of time and has either escaped or was rescued.
- WIA Wounded In Action. This term is used when a soldier is severely injured in battle, rendering them either temporarily or permanently unable to continue active duty.
These classifications were first used by the United States Military.
Due to the need to increase morale in the United Nations Space Command, SPARTAN-II super-soldiers are never listed as 'Killed In Action', but rather as 'Missing In Action' or 'Wounded in Action' to give the appearance that they are invincible.