Who is primarily responsible for all estimates in the Product Backlog?

The Development Team is primarily responsible for all estimates in the Product Backlog because they possess the technical expertise and understanding of the work required to complete the items within. Estimation involves evaluating the complexity, effort, and time required for each Product Backlog item, and the Development Team is best equipped to provide accurate assessments based on their experience and understanding of the technology and the tasks involved.

While the Product Owner manages the Product Backlog and prioritizes its contents, the actual estimation work is collaborative and done by the Development Team. The Scrum framework emphasizes self-organization and cross-functionality among team members, allowing the Development Team to work closely together to determine how much work they can realistically commit to during a sprint. This estimation practice not only aids in planning but also fosters accountability and shared understanding among team members.

The Scrum Master facilitates the process and helps ensure that the team can effectively estimate and commit to work without being impeded by outside factors. However, they do not directly contribute to estimating the work items. Stakeholders may provide input or express their needs and priorities, but they are not involved in the actual estimation of the work required to meet those needs. Thus, the responsibility for estimation primarily lies with the Development Team, aligning with Scrum principles of collective ownership