A system by which firms take on workers, typically young ones, for an initial period of employment during which they spend part of their time training. Training for apprentices may be provided by formal instructional courses, either within the firm or at outside institutions, by learning on the job under the supervision of experienced workers, or in both ways. At the end of their training, apprentices receive some form of formal vocational qualification. Apprentices are frequently paid less than fully qualified workers, and are not guaranteed a job at the end of their training.