When doctors reach consultant level of experience, they can teach Skills to other Doctors. Doctors who attend training sessions improve their ability rating. When Doctors reach a high level of ability, they become eligible for promotion. Promotion is automatic.
When a Doctor is promoted, he undergoes a period of probation. For a Junior being promoted to a Doctor, this period lasts six months. For a Doctor to be promoted to a Consultant, the probation period lasts twelve months. During probation periods, Doctors function at their new level but for the old salary. Note: You cannot build Training rooms until later in the game.
If the Consultant has a particular Surgeon, Psychiatric, or Research Skill, he will train attendee Doctors in these Skills as well. A Consultant with two Skills will pass on both Skills during training. How long it takes to train a Doctor depends on how many Doctors you send for training at any one time. The more Doctors attending a training session, the longer the session takes.
Furnishing the Training Room with Skeletons and Bookcases helps to reduce this length of time. While a Doctor is in training, you can see how far his training has progressed, by calling up the Staff Screen (F6) and selecting the Doctor being trained. The Doctor’s skills are displayed at the bottom of the screen on a bar below the scale in which he’s being trained. This indicates how far the Doctor’s training has progressed.
Training may become essential in later levels, eg. you will be given a single surgeon, and have to hire a consultant to train your single surgeon. This will enable the now consultant surgeon to pass along his training to new doctors in order to fulfil the requirements for certain rooms, such as the Operating Theatre.