<P> A non-commissioned officer (NCO) is a military officer who has not earned a commission . Non-commissioned officers usually obtain their position of authority by promotion through the enlisted ranks . In contrast, commissioned officers hold higher ranks than NCOs, have more legal responsibilities, are paid more, and often have more non-military training such as a university diploma . Commissioned officers usually earn their commissions without having risen through the enlisted ranks . </P> <P> The NCO corps usually includes all grades of corporal and sergeant; in some countries, warrant officers also carry out the duties of NCOs . The naval equivalent includes some or all grades of petty officer . There are different classes of non-commissioned officer, including junior non-commissioned officers (JNCO) and senior (or staff) non-commissioned officers (SNCO). </P> <P> The non-commissioned officer corps is often referred to as "the backbone" of the armed services, as they are the primary and most visible leaders for most military personnel . Additionally, they are the leaders primarily responsible for executing a military organization's mission and for training military personnel so they are prepared to execute their missions . NCO training and education typically includes leadership and management as well as service - specific and combat training . </P> <P> Senior NCOs are considered the primary link between enlisted personnel and the commissioned officers in a military organization . Their advice and guidance is particularly important for junior officers and in many cases to officers of all senior ranks, who begin their careers in a position of authority without practical knowledge and experience . </P>

One of the nco’s chief responsibilities is to