Each Scrum team has a ScrumMaster who guides the process and helps the team deliver optimal results. The ScrumMaster is an expert in the Scrum methodology. He or she is able to identify and remove or mitigate obstacles, facilitate meetings, and communicate clearly with the product owner and other stakeholders.
The ScrumMaster is often someone with a background in project management, but the role can also be filled by a technical specialist. The ScrumMaster is not only a coach, but also a protector of the team. If the product owner is demanding too much, the ScrumMaster must recognize this and help the team members avoid overextending themselves. At the other extreme, if the team members become lackadaisical, the ScrumMaster must address this, too.
Although the ScrumMaster has no real authority over the other team members, he or she is the master of the process itself. The ScrumMaster cannot dismiss team members, but can control the duration and frequency of sprints. The best ScrumMasters keep the team members focused on the end goal, but they do not micromanage in attempts to control how team members perform during each sprint.
The ScrumMaster cannot control how tasks are completed or who completes them, and these limitations to power can be frustrating for those who are accustomed to more traditional roles in project management. The ScrumMaster role is challenging and critical to the success of the Scrum methodology.