Notwithstanding sections 1138.2, 1138.3, 1138.4 and 1138.5, professional employees and temporary professional employees serving as classroom teachers, principals and nonteaching professional employees may be evaluated through the use of a rating tool developed by an individual school district, intermediate unit or area career and technical school that the department has approved as meeting or exceeding the measures of effectiveness established under this subarticle.
24 P.S. § 11-1138.6