Functional leadership model
Functional leadership theory (Hackman & Walton, 1986; McGrath, 1962) is a theory for addressing specific leader behaviors expected to contribute to organizational or unit effectiveness. This theory argues that the leader's main job is to see that whatever is necessary to group needs is taken care of; thus, a leader can be said to have done their job well when contributing to group effectiveness and cohesion. Functional leadership theories are developed by studying successful leaders and identifying the actions and behaviors they show. Extensive studies with a large amount of data make it possible to correlate what  leaders do, i.e., their actions or functions, with their successful results. The Functional theory of leadership emphasizes how an organization or task is being led rather than who has been formally assigned a leadership role. In the functional leadership model, leadership does not rest with one person but rests on a set of behaviors by the group that gets things done. Any group member can perform these behaviors so that any member can participate in leadership. One of the best-known and most influential functional theories of leadership, used in many leadership development programs, is John Adair's "Action-Centred  Leadership". John Adair developed a model of Action-Centred Leadership that has connecting circles that overlap because: Adair's model challenged trait theory by focusing on what leaders do. He showed that leadership could be taught and did not depend on a person's traits. The eight functions of leadership. Adair noted the following 8 key functions for which team leaders are responsible. (Examples are given in brackets) Criticism of the model. Some people consider Adair's Three Circles Model too simplistic and outdated as it was developed in the 1970s. Implications for the nature versus nurture debate. Whether leaders  are born or made is part of the question of whether human behavior is due to nature or nurture. It is a short leap from functional leadership theory to the belief that if one person can do something, others can also learn to do it. The implication that leaders are made and not necessarily born with the necessary traits for leadership opened up the possibility of leadership development.