The scrum master is typically only used in a specific version of Agile called scrum. The following figure illustrates which responsibilities lie exclusively with the product manager (PM), which are shared according to preference and skill between the product owner (PO) and product manager, and which are specifically allocated to a product owner. Use this figure and the later sections on RACI and DACI to have a discussion within your own organization to clarify roles and responsibilities.
Here are definitions of the specific roles:
- Product owner: The mission of the product owner is to represent the customer to the development team. A key activity is to manage and make visible the product backlog, or the prioritized list of requirements for future development. In fact, the product owner is the only person who can change the order of items in the product backlog. One unusual aspect of product owner responsibilities is that she must be available to the development team at all times to answer any questions team members have regarding the customer's view of how they're implementing a product feature.
A product owner shouldn't be a scrum master. In many teams the product manager is also the product owner. This situation leads to a crushing workload and difficult-to-manage expectations because product managers should be spending a fair amount of time understanding customers' needs by being outside of the office. The need to be in the office as a product owner— and yet still have a deep understanding of customers — is a conflict that continues to create great difficulty for product managers and product owners in Agile development organizations.
- Scrum master: The scrum master role is to keep the development team working at the highest level of productivity. This person facilitates scrum rituals that drive the iterations with the scrum team and the product owner. She ensures that scrum processes and scrum-specified meetings are being followed and checks progress against expectations. Critically, she acts as a coach or facilitator for the team, helping team members solve problems and remove impediments to their progress.
The scrum master can be a part time role or shared among multiple scrum teams, but under no circumstances should scrum master be a product owner.