What criteria is used to transfer a child from one phase to another?

The main criteria for transferring a student from one level to the next is their age; however, if we find that a particular student has spent more time than usual in a certain phase or if they have demonstrated skills that will allow them to succeed in the next level, we will form a committee and discuss this on a case-by-case basis. This type of situation is rare, and we would prefer students to remain in their appropriate phase to get the maximum benefit from it.