Page "Corporal" Paragraph 21

Many corporals are found in recruiting units in which specialists are temporarily given a lateral appointment to corporal as an incentive for recruiter duty.

In rare cases, soldiers in regular units are permanently promoted to corporal.

The typical criterion for promotion to corporal is that the junior enlisted soldier must be serving in a leadership position that would typically be occupied by an NCO such as a sergeant or higher.

Normally these promotions are given to specialists who work in an NCO position but who are prevented promotion to sergeant ( E-5 ) due to promotion point quotas.