In addition to the other requirements of this subtitle, movement up the career ladder shall depend on: The teacher’s performance; The teacher’s experience; and The availability of positions. A teacher may not be promoted to the next level or tier on the career ladder unless: The most recent evaluation of the teacher’s instruction by the principal or other individual, as determined by the county board, is effective; The teacher and the principal, supervisor, or any other individual, as determined by the county board, agree that the teacher is ready to take on the additional responsibilities required by the position at the next level; and There is an open position at the next level. Promotion up the career ladder is not guaranteed. In choosing a candidate for an open position in the career ladder, consideration shall be given to the candidate’s experience in schools that represent the demographic and economic diversity of the school system. As a teacher moves up the career ladder and receives effective evaluations, the teacher shall be given increased authority, responsibility, and autonomy for making school–level decisions. Movement from one level or tier to a higher level or tier shall result in a salary increase consistent with § 6–1009 of this subtitle. A teacher may move from one track of the career ladder to a different track with the approval of the principal of the school in which they teach.