An individual must complete and pass all required training for their military occupational specialty qualification (MOSQ).
Originally, the four-digit MOS code mostly listed the recruit's civilian profession.
With so many recruits being processed, identifying any semi-skilled or skilled civilian tradesmen made it easier to match them with the right military job.
There were no grouping of similar trades together, making it hard for someone to know the meaning of an MOS code without a manual.
The MOSC is used with active and reserve records, reports, authorization documents, and other personnel management systems.
Some MOS do not change though, for example 25U starts out as 25U1O (E1-E4), and advances though 25U2O (E5/SGT), 25U3O (E6/SSG), 25U4O (E7/SFC), and 25U5O (E8, E9/MSG, 1SG, SGM, CSM) Warrant officers are sometimes specialized technicians and systems managers, and were not originally assigned to traditional arms or services of the Army.
In practice, warrant officer MOSC are very similar to enlisted codes except they begin with three digits instead of two before the first letter, and do not have a "skill level" identifier.
After an officer's fifth or sixth year of service, he or she may receive a "functional area" designation.
The fields are numbered from 01 to 99 and include general categories (intelligence, infantry, logistics, public affairs, ordnance, etc.)
[10] Each field contains multiple MOS's, each designated by a four-digit numerical indicator and a job title.
A Marine who earns an NMOS retains it in their service records as an additional MOS beyond their PMOS, and multiple NMOS's (and PMOS's, in some cases) may be earned showing additional skills.
For example, the infantry field (03) has multiple enlisted classifications: Each of the jobs have authorized ranks associated with them.
On September 29, 2016, the Navy announced it would "modernize" all rating titles for Sailors with a new classification system that would move towards occupational specialty codes similar to how the other services operate.
Former Master Chief Petty Officer of the Navy Michael Stevens led the controversial review earlier that year for the Secretary of the Navy on behalf of Chief of Naval Operations, Admiral John Richardson.
The former Master Chief Petty Officer of the Navy, Steven S. Giordano, said: "Sailors would no longer be called, 'Yeoman Second Class' or YN2, for example," he said.
As a result, Admiral Richardson rescinded this change on December 21, 2016, restoring all rating titles.
[11] However, the plan retains the goal of producing sailors with more than one NOS, which might give them a broader range of professional experience and expertise and will be grouped under career fields that will enable flexibility to move between occupational specialties within the fields and will be tied to training and qualifications.
The transformation will occur in phases over a multi-year period and the Chief of Naval Personnel will lead the implementation efforts The United States Navy has not released its NOS details yet and has not changed "designators" for officers.
These range from ABE (aviation boatswain's mate – equipment) to YN (Yeoman).
The navy officer "designator" is similar to an MOS but is less complicated and has fewer categories.
A reserve surface warfare officer specializing in nuclear training (i.e., engineer on a carrier) has a designator of 1165N.
Navy officers also have one or more three-character additional qualification designators (AQD) that reflect completion of requirements qualifying them in a specific warfare area or other specialization.
Navy officer designators and AQD codes may be found in NAVPERS 15839I, The Manual of Navy Officer Manpower and Personnel Classification.ip The United States Coast Guard does not use the military occupational specialty concept either, instead dividing their occupational specialties into groups such as aviation, administrative and scientific, deck and weapons, and engineering and hull.