The product backlog is maintained thorough product backlog refinement
§ Refinement is the continuous act of adding detail, estimates, and order to items.
§ Product Backlog refinement is the responsibility of the Product Owner.
§ The Product Owner, however, may enlist the help of the Development Team to refine the Product Backlog.
§ Refinement should not take up more than 10% of the Development Team’s time.
§ The Development Team may create and add new Product Backlog items to assist the Product Owner. The Product Owner, however, remains accountable and should always be the gatekeeper to the Product Backlog.
§ The higher the order of the Product Backlog item, the more refined it should be.
§ The Product Backlog should contain enough “ready” Product Backlog items to occupy the Development Team for the next sprint so they may be selected by the Development Team to be “done” in the sprint planning event and accomplish a Sprint goal.
§ Product Backlog refinement is not an official Scrum event. Instead, it is an ongoing activity.
§ The Product Owner and the Development Team collaborate in the refinement process as an ongoing activity.