Quote Originally Posted by FactionHeir
Err what are OOB?!
An order of battle (often abbreviated as ORBAT, OOB, O/B, or OB) is an organizational tool used by military intelligence to list and analyze enemy military units. In United States Army practice, an order of battle should relate what an American unit might be expected to encounter while on field operations. Orders of battle analyze enemy units, personnel, and equipment.

The United States Army breaks down an order of battle entry by the following factors:

Composition: the command structure and organization of headquarters and subunits
Disposition: geographical locations of unit headquarters and subunits
Strength
Training
Tactics used by the enemy unit
Logistics: how the enemy unit obtains its supplies
Combat Effectiveness
Electronic Technical Data
Miscellaneous
Personalities
Unit history
Uniforms and insignia


Source: http://en.wikipedia.org/wiki/Order_of_battle

I would have described it myself but this is far more definitive and a decent read. :)