While, in reality, the Chair and the Facilitator are often the same person, each role has different and distinct responsibilities. The Chair is the elected (or appointed) head of the team. The Chair is responsible for the meeting's outcomes and work product. The facilitator is responsible for the process of the meeting(s). This includes making sure that the groundrules are being followed, the agenda is being followed and the participants are engaged and on-task. It is often good practice to separate the jobs of Chair and Facilitator.
When might the Chair choose to facilitate him/herself or ask another member of the group to facilitate?
When would it make sense to invite an outside facilitator?