The United States Army uses a complex organizational system to categorize enlisted men and women by Military Occupational Specialty (MOS). An Army MOS is a specific job within the complex command structure of the United States Army, ranging from playing the trumpet for the Army band to rigging parachutes for the quartermaster corps. Commissioned officers in the Army are categorized under Areas of Concentration (AOC), rather than under the MOS system, although the two systems are very similar.
The Army breaks down Specialties by “career management field,” a reference to a large category such as “engineering” or “military intelligence.” Within each career management field, individual Military Occupational Specialties can be found. The entire system is accompanied with a set of codes, so someone with the Army MOS 98P, for example, is a multi-sensor operator in military intelligence. These alphanumeric codes are designed to be flexible as specialties are added and eliminated to reflect the changing nature of the military. MOS and AOC codes have also been streamlined so that similar codes are used for enlisted people and commissioned officers in the same field.
According to the Army, as of 2008, infantry, field artillery, air defense, aviation, special forces, armor, engineering, signals, military police corps, judge advocate special branch, military intelligence, army band, psychological operations, civil affairs, adjutant civil branch, finance, public affairs, chaplain branch, mechanical maintenance, medical, chemical warfare, recruiting and retention, transportation, ordnance branch, quartermaster corps, and electronic maintenance are all career management fields. Within each of these fields, people have a number of potential careers to pursue.
Jobs in the Army are quite diverse, with people typically picking or being placed into specialties for which they are best suited. In addition to soldiers, the military also needs doctors, accountants, supply managers, and so forth, and many of these jobs offer training which can be used in the civilian world as well as in the military. People can also develop an Army MOS as a lifetime career, gaining military rank in the process.
There are some limitations in the Army MOS system. Women, for example, cannot serve in certain combat positions, and as a result, not every Army MOS is open to them. Other positions require people to be able-bodied, so someone who becomes disabled as a result of military service may be moved to a different Army MOS if he or she wishes to continue serving. All MOSs typically require an ability to relocate where needed. The Marine Corps also uses the MOS system, while the Air Force refers to “Air Force Specialty Codes,” and the Navy and Coast Guard use “Ratings.”