Who is ultimately responsible for the estimates of Product Backlog items?

The Development Team is ultimately responsible for the estimates of Product Backlog items because they are the ones who have the technical expertise and understanding of the work involved. During the Sprint Planning meeting, the Development Team assesses the complexity and effort required to complete each item in the Product Backlog, using methods like Planning Poker or relative estimation techniques.

This responsibility makes sense as they are the ones who will be doing the actual work. Their insights help establish a realistic understanding of what can be accomplished within a Sprint, ensuring that commitments made to the Product Owner and stakeholders are based on informed assessments.

While the Product Owner is responsible for maintaining the Product Backlog and defining the items within it, the responsibility for estimating how difficult or time-consuming these items will be rests with the Development Team. This collaboration emphasizes the self-managing aspect of the Scrum teams, where the developers hold authority over their own work and commitments.