Pierluigi Pugliese is a software consultant and agile coach whose views on coaching have influenced on my own over the last few years. (I've particularly appreciated learning about the many parallels between agile coaching with developers and executive coaching with leaders.)
Pugliese recently gave a presentation in Prague on The Scrum Master as a Team Coach, and his deck included a diagram similar to the one above. He notes that a coach working with a software development team will play these eight roles, and going a step further, I find this a compelling model for the range of roles that must be played by every leader in any group.
I've re-organized Pugliese's schema by pairing up the roles along four axes, each of which represents a different dimension of leadership behavior, and the definitions below are my own, so don't blame Pugliese if you disagree.
Expert vs. Coach
The primary leader archetypes: the Expert with the answers, whose extensive domain experience is the basis for their authority, and the Coach with the questions, whose expertise lies in helping people discover the answers for themselves.
Evangelist vs. Motivator
Our word "evangelist" derives from the Greek "euangelistes," which means "bringer of good news." The Evangelist is on a mission to spread a message, and their goal is to rally others to their cause. The Motivator is agnostic, seeking to identify others' personal goals and help them move forward in their preferred direction, whatever it may be.
Trainer vs. Mentor
The Trainer is focused on the task at hand and shows others what is to be done (and how to do it better). The Mentor is focused on others' development, and immediate tactical performance is secondary to long-term strategic growth.
Mediator vs. Facilitator
The Mediator seeks to resolve conflict and maintain harmonious relationships in the service of group effectiveness. The Facilitator seeks to maximize learning and ensure that all voices are heard in the service of candor, integrity and authenticity.
Looking over this framework, I'm reminded of a passage from Peter Drucker's Management Challenges of the 21st Century:
Increasingly "employees" have to be managed as "partners"--and it is the definition of a partnership that all partners are equal. It is also the definition of a partnership that partners cannot be ordered. They have to be persuaded...
One does not "manage" people.
The task is to lead people.
And the goal is to make productive the specific strengths and knowledge of each individual. [Emphasis original, pp 17-22]
And of this comment from Bill George:
We need to disavow ourselves of the notion that leadership is power over other people. Leadership capacity is the ability to empower other people to step up and lead.
The better we can fulfill the Coach / Mentor / Motivator roles as leaders, the more effectively we can meet the challenges posed by Drucker and George (and the many others who've expressed similar thoughts in recent decades.)
But that's not to say the Expert / Evangelist / Trainer roles are unhelpful--they're essential leadership tools, particularly early in a group's development or when leading the inexperienced. Note that in Daniel Goleman's research on leadership styles (discussed in his classic HBR article, Leadership That Gets Results), the style with the greatest positive impact on "climate," his term for working atmosphere, is the Authoritative style, which he describes as follows:
An authoritative leader takes a "Come with me" approach: she states the overall goal but gives people the freedom to choose their own means of achieving it. This style works especially well when a business is adrift. It is less effective when the leader is working with a team of experts who are more experienced than he is.
To me the question isn't "What type of leader am I?" but rather "Can I adjust my leadership style to best fit the needs of the situation? Am I flexible and adaptable as a leader? Can I sense what is called for and deliver it?"