Along with this movement toward greater accountability was the increasing number of research studies attempting to measure the impact of school leadership. New terms began to emerge in literature such as: shared leadership, teacher leadership, distributed leadership and transformational leadership. “The emergence of these models indicated a broader dissatisfaction with the instructional leadership model, which many believed focused too much on the principal as the centre of expertise, power, and authority” (Hallinger, 2003, p. 330).