The ScrumMaster is there to help, coach, provide a consultancy role, and look at the project from all angles. The project remains the responsibility of the product owner, and it's up to him or her to make the final decisions. However, the product owner can look to the ScrumMaster to help answer questions about user experience, functionality issues, user feedback, and any need to realign the development to fit with changes outside the business. The ScrumMaster helps the product owner understand how to effectively manage the work of the team, using the product backlog and the planning and review meetings.

ScrumMaster has to coach the product owner to understand how to achieve the goals and how to continually adapt and prioritize the backlog. The ScrumMaster is the link between the product owner and the team.

There is often a lot of noise from within the business, and it's down to the product owner and the ScrumMaster to protect the team from that noise. Changes in what is being developed should be communicated via the product owner and nobody else.

Traditionally, the project manager is a leader, a decision maker, a planner, someone who manages the project and the team and is the person accountable to the business for accomplishing the project objectives. The ScrumMaster's role is more that of coach and facilitator, a role that sits between the project and the customer. The ScrumMaster doesn't manage the team that produces the work; instead, he supports the product owner, coaches the team, and makes sure that Scrum processes are adhered to. The ScrumMaster is responsible for the Scrum process, its correct and continuous implementation, and the maximization of its benefits.

Contrary to popular belief, the ScrumMaster and project manager roles are highly different and shouldn't be confused. As more companies migrate their project management to Agile, many do so without a proper understanding of what they're aiming for.