The ‘L’ Factor describes the indications that a person will be able to handle the role and complexity of leadership, the importance of belief system and the role of emotional intelligence. It presents a model of 5 levels of leadership complexity and how these levels provide a context in which leaders can be developed.
There are some helpful stories here. It includes Jagelman's own paradigm of ministry v leadership; 5 levels of leadership: and some scenarios to land his ideas.