The term "school leadership" came into existence in the late 20th century for several reasons. Demands were made on schools for higher levels of pupil achievement, and schools were expected to improve and reform. These expectations were accompanied by calls for accountability at the school level. Maintenance of the "status quo" was no longer considered acceptable. "Administration" and "management" are terms that connote stability through the exercise of control and supervision. The concept of leadership was favored because it conveys dynamism and pro-activity. The principal or school head is commonly thought to be the school leader; however, school leadership may include other persons, such as members of a formal leadership team and other persons who contribute toward the aims of the school.