Sec. 19. "Supervisor" means an individual who has:
(1) authority, acting for the school corporation, to hire, transfer, suspend, lay off, recall, promote, discharge, assign, reward, or discipline school employees;
(2) responsibility to direct school employees and adjust their grievances; or
(3) responsibility to effectively recommend the action described in subdivisions (1) through (2);
that is not of a merely routine or clerical nature but requires the use of independent judgment. The term includes superintendents, assistant superintendents, business managers and supervisors, directors with school corporationwide responsibilities, principals and vice principals, and department heads who have responsibility for evaluating teachers.