I like butter, and when I eat a piece of freshly baked bread, a good hunk of butter thickly spread is an essential ingredient. I don’t skimp on the butter. Using the butter for one piece of bread and spreading it across two or three slices saves cost, but at what price!? Why, the price is my enjoyment.
So how does this relate to Process Facilitators?
Sometimes, organizations try to “optimize” their costs by spreading Process Facilitators thinly. This is a false economy. Having a Process Facilitator for multiple teams is probably better than having no Process Facilitator, but if the organization really believes in the value of the work the team is doing, and the value of the removal of obstacles, then there should be no problem having one Process Facilitator per team.
I strongly advise that there be only one Process Facilitator per team for the simple reason that the Process Facilitator is a member of the team. The Process Facilitator does not _individually_ commit to the team’s goal for an iteration, but the Process Facilitator must feel a great deal of responsibility for that goal given that this person is responsible for tracking, facilitating and in some cases actually removing obstacles to the team’s ability to meet its goal. As well, the Process Facilitator protects the team from new impediments.
I think that for rare individuals with relatively established teams, it would be possible to be the Process Facilitator for more than one team effectively. Remember that the ideal team size is 7+/-2. For much smaller teams, (4 or fewer people), you might find that having a single person dedicated to the role of Process Facilitator is too much overhead. But rather than sharing one Process Facilitator across multiple small teams, consider having one individual on each team who has some substantial portion of their time dedicated to those duties.
A Process Facilitator who is not part of the team cannot be properly informed of the needs, difficulties and successes of the team. This only leads to frustrated teams, frustrated Process Facilitators and organizations that improve much more slowly than they could.
Never spread your Process Facilitator too thin.