There are three roles in scrum: Product Owner, Team, and Scrum Master. Together they are called The Scrum Team.
The Product Owner is accountable for optimizing return on investment (ROI) by analysing product aspects, converting these into a priority-wise list so as to decide those things which should be at the top of the list for the next Sprint, and continuously changing the priority based on analysis and recreating the list. The Product Owner is responsible for profit and loss of the product, supposing it is a retail product. In case of an internal operation, the Product Owner is not accountable for ROI unlike in the case of commercial product (which generates revenue); however they are still accountable for maximizing ROI. The Product Owner and the customer might be the same person in few cases. This usually happens in case of internal applications. In other cases, the customer might be millions of people with various requirements. In such scenarios, the Product Owner title is similar to the Product Manager or Product Marketing Manager position.
The Development Team creates the commodity that the Product Owner requires to go ahead. The Team in Scrum is “cross-functional” – so that they can contribute accordingly as per the increment which is required to come with the product. As the team is cross-functional, so they promote multiple learning. Each person in the team has some specialization and keep on learning other specialties as well as that might be required for the project.
The Team should be available throughout the project. They shouldn’t split their time to other projects while handling this project. Their responsibility is to self–organize themselves to achieve each goal and creating the product as per each sprint plan. Once the product owner makes a complete list of things to be done, the development team members foretell how much they can do in one sprint, and they further decide how they will accomplish it.
The Scrum Master helps the development team to learn and apply Scrum skills to achieve business value. The Scrum Master help the Team, Product Owner and the organization with their knowledge, skills and by whatever means to become more and more successful. The Scrum Master is not the leader of the Team members, nor are they a project manager or team representative. However, the Scrum Master’s job is to serve the Team. They help to remove barriers to project, protect the Team from any outside conflict, and help the Team to adopt modern development practices.