Who decides how much is moved from the product backlog to the iteration backlog?

The determination of what amount is moved from the product backlog to the iteration backlog is fundamentally a collaborative decision made by the team members. This process typically occurs during iteration planning sessions where the entire team, including developers and the Product Owner, assesses the priorities and capabilities to define what can reasonably be accomplished in the upcoming iteration.

Team members discuss the items in the product backlog, consider their complexity, the team's capacity, and the overall goals for the iteration. This collaboration ensures that the team collectively commits to a realistic set of tasks based on their understanding of their abilities and the work required.

While the Product Owner plays a crucial role in prioritizing the items in the product backlog based on value and stakeholder feedback, it is ultimately the development team that decides how many and which specific items they can take on in an iteration, fostering a sense of ownership and accountability within the team.