The Scrum Team needs a great deal of help from their ScrumMaster. This help includes: removal of obstacles, advancement and reminders of the Scrum principles and practices, ongoing facilitation of effective Scrum meetings, accompaniment of the Team Members to develop new skills, building of relationships with those outside the team, and ongoing advancement of the use of Scrum by the team. With all of this, the ScrumMaster responsibilities are quite difficult to master. The ScrumMaster must prioritize the most important work to be done, possibly using a list much like the Product backlog. If the ScrumMaster is working with two teams, for example, at some point in time he will have to decide which team to work with for a given problem. Which team is more important? If he choses another team, won’t the other team feel left out and un-protected? One of the most important duties of a ScrumMaster is to remove obstacles as the team identifies them in a timely manner. This responsibility is extremely difficult in some ways since many obstacles have cultural or organizational issues at their root. For a Scrum team to be effective, it needs a ScrumMaster who is full-time. One way to imagine this question is by comparison to a sports team. If the team is a bunch of kids doing the sport for recreational reasons, then its perfectly legitimate to have the coach also working with other kids teams. Not much is on the line. On the other hand, if the team is a professional, world-class team, you would never accept a coach who also wanted to work with another world-class team. The time, the conflict of interest would not allow such an arrangement. Do you want world-class, high performance Scrum Teams? The ScrumMaster should only work with one Scrum Team.
To learn more about working with only one scrum team, visit the Scrum Team Assessment.