On or before July 1, 2024, each county board shall implement a career ladder that meets the requirements of this subtitle. Except as otherwise provided in this subtitle, the requirements of this subtitle shall become effective in a county on the date the county board adopts a career ladder under paragraph (1) of this subsection. There is a career ladder for educators in the State. The purpose of the career ladder is to: Transform teaching into a high–status profession in the State; Attract high–performing students to pursue the high–status teaching profession; Retain high–quality teachers who gain additional responsibility, authority, status, and compensation as they gain additional expertise; Transform the education system in the State into a top–performing system in the world; Support the reorganization of schools to provide teachers with professional learning and peer collaboration time during the school day by having more teachers in each school, including time primarily: To work in teams of teachers by subject and grade; To work together with other teachers to continuously improve instruction; To review together with other teachers individual student needs, including needs related to behavioral issues, and develop plans to address those needs; and For professional learning for teachers pursuing NBC; Develop and support highly competent school leaders that are able to lead high–performing schools due to their: Knowledge of teaching and learning; Experience as teachers, leaders, and mentors of teachers; and Knowledge of and experience with organizing schools so that all students are successful in the global economy; and Above all, inspire teachers and school leaders to instill in their students a passion for learning and a mastery of the skills necessary to succeed in the global economy. Except as provided in this subtitle, the career ladder is subject to collective bargaining in accordance with § 6–408 of this title. The career ladder shall: Adequately compensate professional teachers for their work; Support and encourage teachers working in teams to systematically improve schools and curricula; Provide teachers with the opportunity to identify and work with students who need extra help, including by providing teachers time during the school day to take on those pursuits; and Provide teachers with the opportunity to develop their skills and knowledge by participating in job–embedded professional development. The guiding principles for development of the career ladder are: Progression of teachers in a manner that incentivizes teachers to stay on the teacher track rather than moving to the administrator track; A teacher salary that attracts new teachers to the profession; A teacher salary that incentivizes existing teachers to opt in to the career ladder; Teacher salary progression as performance increases as demonstrated by a teacher achieving NBC; and Incentives that are successful in all local school systems. The levels of the career ladder are as follows: Level one is a State certified teacher; Level two is a teacher pursuing: A master’s degree; 30 credits of a program of study approved by the State Board, in consultation with the Professional Standards and Teacher Education Board; or NBC; Level three is: An NBC teacher; If there is no assessment comparable to NBC for the teacher’s subject area, a teacher with a master’s degree in the teacher’s subject area; or An assistant principal; and Level four is: A teacher on the teacher leadership track, in the following tiers: Lead Teacher; Distinguished Teacher; or Professor Distinguished Teacher; or A teacher on the administrator track, in the following tiers: Licensed Principal; or Distinguished Principal. If a teacher achieves level three or four of the career ladder by being an NBC teacher, the teacher shall maintain an active National Board Certification in order to remain on level three or four of the career ladder, as applicable. Subject to paragraph (2) of this subsection, teachers at each level or tier of the career ladder shall teach in the classroom for a minimum percentage of their total working time, as specified in this subtitle. The percentages referenced in paragraph (1) of this subsection shall become effective in phases over a 7–year period beginning July 1, 2028, as specified by a county board on approval of the State Board. The following teachers shall be given priority for working time outside the classroom as the percentages referenced in paragraph (1) of this subsection are phased in: Newly licensed teachers, particularly new teachers in low–performing schools or schools that have a high concentration of students living in poverty; and Teachers in schools that: Are low–performing; Have a high concentration of students living in poverty; or Have large achievement gaps between subpopulations of students. The percentage of teachers who are Professor Distinguished Teachers or Distinguished Principals may not be more than 1% of the total number of all teachers. Teachers in the upper levels of the career ladder shall mentor teachers in the lower levels of the ladder, especially those teachers who teach in schools with high proportions of low–performing students. Each county board shall strive to place NBC teachers in schools throughout the county and in a manner that supports equity and prioritizes low–performing schools. A county board may not receive funding from the State for the implementation of the career ladder under § 6–1009 of this subtitle unless the county board implements a career ladder that meets the requirements of this subtitle.