United States Marine Corps (USMC)
Officer Job Descriptions
Explanation of Terms
Category I MOSs are suitable for assignment to unrestricted Regular/Reserve officers; Category II MOSs are suitable for assignment to LDOS; Category III MOSs are suitable for assignment to regular/reserve warrant officers.
A Roman numeral appearing after an MOS title indicates the appropriate officer category for that MOS. MOSs will be assigned as primary MOSs only to officers who are in the designated categories.
MOSs which do not have Roman numeral designations in the title line may be assigned to any qualified officer as an additional MOS or as a skill designator MOS, except for billet designators.
OCCUPATIONAL SYSTEM. The Marine Corps Occupational System has been constructed on the concept that occupations of similar skill and knowledge requirements are grouped in functional areas, known as OccFlds, which provide for the most efficient and effective classification, assignment, and utilization of Marine Corps personnel. The officer occupational system identifies Marine Corps commissioned and warrant officer duties, skill attributes, and requirements within the specific functional areas. See additional material in paragraph 0005 of the Introduction.
MOS SYSTEM. The MOS system consists of a four-digit number used in conjunction with a descriptive title to identify Marine Corps occupations and personnel.
OccFld. The OccFld is identified by the first two digits of a four-digit number and a descriptive title. The OccFld is a grouping of related MOSs. Criteria to be considered in establishment of an OccFld include the total number of Marines in the field, the number of MOSs (diversity), combat or combat support requirements, rotation base, and training requirements.
MOS
The MOS describes a group of skills and related duties that extend over one or more grades. Each MOS consists of a four-digit code and a descriptive title.
MOS numbers ending in 01-10 or any multiple of 5 are reserved for officer MOSs, except for MOS numbers of 9600 or higher.
Skill designator MOSs. A nonprimary MOS. May be found in Category "B' MOSs or in regular OccFlds Skill designator MOSs within Occflds are usually low density MOSs that require foundation skills acquired in a related primary MOS. Examples from OccFld 02: Primary MOS 0210 with skill designator MOS 0215.
Symbols. The following symbols are used throughout the MOS Manual:
1. * - indicates a skill designator MOSs.
2. # - indicates there is a note at the end of the MOS.
Primary MOS (PMOS)-- Identifies the primary occupational classification of a Marine. Marines are promoted in their PMOS, and changes to an individual Marine's PMOS without approval from HQMC
(MM)-- are not authorized.
Additional MOS (AMOS)-- Any existing PMOS awarded to a Marine who already holds a PMOS. Marines are not promoted in an AMOS.
Skill Designator-- A non primary MOS. May be found in Category "B" MOSs or in regular OccFlds. Skill designator MOSs within OccFlds are usually low density MOSs that require foundation skills acquired in a related primary MOS. Example from OccFld 35: Primary MOS 3521 with skill designators 3522, 3523, 3524, 3525.
Category "B" MOS -- MOSs 8000-9599 (except 8412). Enlisted only billet MOSs, non-PMOS, appearing on T/Os where special skills or an accounting for structure is required. The overall population is not managed as a community. Marines are promoted by PMOS even while serving in Category "B" billets.
Core Skills -- Those essential basic skills that "make" a Marine and qualify that Marine for an MOS. Core skills comprise the set of core tasks for each MOS as found in the Individual Training Standards (ITS), or Training and Readiness (T&R) Manual.
*Core skills have not yet been identified for all MOSs. Moss not having core skills in the ITS will have Task-to-Standard designation or "S".
Core Plus Skills Tasks that are mission advanced, rank, or billet specific. These tasks are taught, executed, and evaluated at the unit level.
Required Training -- Training normally expected to be received by Marines after completion of recruit training, where core skills training is provided at an MOS producing formal school course. This is not to imply that it is only source of MOS qualifying training.
Skills Progression -- Formal schools training for Marines already holding Training an MOS, but the training relates directly to increasing overall skills and knowledge in the MOS. All holders of the MOS might be expected to attend, if available.
Skill Enhancement -- Formal school or structured training for Marines already holding an MOS. Relates directly to increasing overall skills in the MOS. Usually intended for MOS holders with particular billet requirements.
Information Derived From MCO P1200.7V Part 1. Current as of Nov 00
