You understood the scrum roles in brief earlier. Let us take a closer look at them.

Teams:

They may write a few user-stories but their main work is to elaborate and implement the user-stories.

During the sprint planning, the team members do the estimation. They estimate how much work each story represents. This is done as a team activity as teams are better at estimating work than individuals.

The teams determine the scope of the sprint and make the commitment. In non-agile environments the management determines the scope and gets the team to deliver. In Agile the teams determine the scope based on the priorities specified by the product owner and they make the commitment to deliver that scope by the end of the sprint together.

In Agile, an important trait of team-members is that they have a T-shaped skill set i.e. generalized specialists. The idea is that the best team members have a deep knowledge in a few areas and have a good overall domain knowledge. This is critical as Scrum does not have project managers assigning work to people. Team-members should be able to go into the backlog and choose work to do themselves. This is a very effective and progressive way for teams to work. Teams are very empowered in Scrum and they deliver much more reliably than non-agile teams.

Product Owner:

They are 100% dedicated to the team and product i.e. they work full time with one team and one project. However, this is an ideal situation. In the real world, the PO may work on multiple projects and distribute his/her time accordingly.

They are the customer/stakeholder interface for the team.

Usually the stakeholders have conflicting opinions and goals and it is the job of the PO to resolve them and present a coherent picture to the team and give the team a single & solid direction to work.

They own the higher-level strategic elements of the business like the strategy, vision and business case.

They also own user stories. They write and prioritize the user stories.

They own the Product Backlog but not the Sprint Backlog which is managed by the team.

POs often has challenges with analysis-related work.

They are product-oriented people with good high-level product knowledge. They may write user stories but may still need help with writing acceptance criteria, user-story splitting, visual modeling, and other analysis-related work.

Scrum Master

They are NOT Project Managers.

They don’t manage the team or project. In Agile, the team manages itself.

They are servant leaders. They assure that the team and product owner have all the resources to get the work done.

They can be thought of as catalysts. They don’t create anything tangible by themselves but they facilitate everything getting done.

Unique Responsibilities:

• Run meetings.
• Broadcast information to the team.
• Coordinate with management.
• Above all: Resolve Obstacles! The scrum master handles the problem so that the team can develop the product.

Important Points:

The team is responsible for estimating the amount of work of each feature, determining the scope of each sprint, and making the scope commitment to the business. The team performs these tasks together, rather than having a team leader or manager doing them.

The PO is primarily responsible for writing the majority of user stories and managing the product backlog. Although anyone can write user stories, the responsibility to create them and prioritize them as part of the product backlog belongs to the PO.

It’s the ScrumMaster’s responsibility to overcome the obstacles that the team is facing, so they can be as effective as possible. Hence, they can be thought of as “servant leaders”.