The ScrumMaster is responsible for ensuring that everyone related to a project, whether chickens or pigs, follows the rules of Scrum. These rules hold the Scrum process together so that everyone knows how to play. If the rules aren’t enforced, people waste time figuring out what to do. If the rules are disputed, time is lost while everyone waits for a resolution. These rules have worked in literally thousands of successful projects. If someone wants to change the rules, use the Sprint retrospective meeting as a forum for discussion. Rule changes should originate from the Team, not management. Rule changes should be entertained if and only if the ScrumMaster is convinced that the Team and everyone involved understands how Scrum works in enough depth that they will be skillful and mindful in changing the rules. No rules can be changed until the ScrumMaster has determined that this state has been reached.
The Sprint planning meeting is time-boxed to 8 hours and consists of two segments that are time-boxed to 4 hours each. The first segment is for selecting Product Backlog; the second segment is for preparing a Sprint Backlog.
The attendees are the ScrumMaster, the Product Owner, and the Team. Additional parties can be invited by any of these people to provide additional business domain or technology domain information and advice, but they are dismissed after this information is provided. There are no chickens as observers.
The Product Owner must prepare the Product Backlog prior to the meeting. In the absence of either the Product Owner or the Product Backlog, the ScrumMaster is required to construct an adequate Product Backlog prior to the meeting and to stand in for the Product Owner.
The goal of the first segment, or first 4 hours, is for the Team to select those Product Backlog items that it believes it can commit to turning into an increment of potentially shippable product functionality. The Team will demonstrate this functionality to the Product Owner and stakeholders at the Sprint review meeting at the end of the Sprint.
The Team can make suggestions, but the decision of what Product Backlog can constitute the Sprint is the responsibility of the Product Owner.
The Team is responsible for determining how much of the Product Backlog that the Product Owner wants worked on the Team will attempt to do during the Sprint.
Time-boxing the first segment to 4 hours means that this is all of the time that is available for analyzing the Product Backlog. Further analysis must be performed during the Sprint. Large-grained, high-priority Product Backlog with imprecise estimates might not be thoroughly understood during this part of the Sprint planning meeting and might result in the Team not being able to complete all of the Product Backlog that it selects.
The second segment of the Sprint Planning meeting occurs immediately after the first segment and is also time-boxed to 4 hours.
The Product Owner must be available to the Team during the second segment to answer questions that the Team might have about the Product Backlog.
It is up to the Team, acting solely on its own and without any direction from outside the Team, to figure out during the second segment how it will turn the selected Product Backlog into an increment of potentially shippable product functionality. No one else is allowed to do anything but observe or answer questions seeking further information.
The output of the second segment of the Sprint planning meeting is a list, called the Sprint Backlog, of tasks, task estimates, and assignments that will start the Team on the work of developing the functionality. The task list might not be complete, but it must be complete enough to reflect mutual commitment on the part of all Team members and to carry them through the first part of the Sprint, while the Team devises more tasks in the Sprint Backlog.