Scrum events and timeboxes: Sprint Planning to Retrospective
Scrum has five events: the Sprint, which contains Sprint Planning, the Daily Scrum, the Sprint Review and the Sprint Retrospective. Each is a formal chance to inspect and adapt, and each has a maximum length, called a timebox.
The events and their timeboxes
The Sprint is a fixed length of one month or less, and the next starts as soon as the previous ends. Sprint Planning sets the Sprint Goal, selects items and plans the work, in at most eight hours for a one-month Sprint. The Daily Scrum is 15 minutes for the Developers to inspect progress toward the Sprint Goal and adapt the plan. The Sprint Review is at most four hours, and the Sprint Retrospective at most three. Shorter Sprints usually have shorter events.
The Scrum Master makes sure the events take place and stay within their timebox.
Rules scenarios turn on
During the Sprint no changes are made that would endanger the Sprint Goal and quality does not decrease, but scope may be clarified and renegotiated with the Product Owner as more is learned. If one selected item turns out far larger than forecast, the Developers renegotiate scope with the Product Owner. They do not extend the Sprint or cut testing.
Only the Product Owner can cancel a Sprint, and only when the Sprint Goal becomes obsolete.
The Daily Scrum is for the Developers. If the Product Owner or Scrum Master is actively working on Sprint Backlog items, they take part as Developers. Detailed discussions can happen at other times during the day.
Review versus Retrospective
The Sprint Review inspects the product outcome with key stakeholders and decides what to do next; the Product Backlog may be adjusted. The Scrum Guide calls it a working session and says the team should avoid limiting it to a presentation.
The Sprint Retrospective inspects how the Sprint went for individuals, interactions, processes, tools and the Definition of Done, and plans ways to improve quality and effectiveness. It concludes the Sprint.
Where the exam catches people
Believing the Sprint can be extended to finish late work: Sprints are fixed length, so scope is renegotiated instead.
Believing a Sprint can be cancelled because urgent work arrived: it can be cancelled only when the Sprint Goal becomes obsolete, and only by the Product Owner.
Believing the Sprint Review is a demo: the Scrum Guide calls it a working session where attendees collaborate on what to do next.
Believing the Product Owner never attends the Daily Scrum: a Product Owner working on Sprint Backlog items takes part as a Developer.