Which tier of training follows the initial skill level in Services?

The tier of training that follows the initial skill level in Services is the five-level. In the context of the Enlisted Training Structure, the progression typically includes several tiers: after achieving the three-level, which represents the initial skill set, the five-level represents the next stage where an Airman gains more advanced technical knowledge and practical experience in their field. This level involves additional training, often requiring completion of certain courses and a minimum amount of on-the-job training. Advancing to the five-level indicates that the individual has developed greater competency in their role and can perform more complex tasks independently. This structure ensures that personnel are well-prepared to meet increased responsibilities and expectations as they progress in their careers.