Product Backlog is a prioritized list of desired product functionality.
The Product Backlog provides a centralized and shared understanding of what to build and the order in which to build it. It is a highly visible artifact at the heart of the Scrum framework that is accessible to all project participants. It is the single source from which all requirements flow. This means that all the work the Development Team does comes from the Product Backlog.
The Product Backlog is composed of backlog items, which we refer to as PBIs, backlog items, or simply items. Every feature, idea, enhancement, bug fix, documentation requirement and any other work the Product Owner deems valuable – every bit of the work they do – is derived from a Product Backlog Item. Each item on the Product Backlog includes a description and an estimate. In most organizations the Product Backlog Items also have a Business Value recorded against them to help with prioritization.
Good Product Backlogs exhibit similar characteristics. Several important characteristics, referred as DEEP – Detailed appropriately, Emergent, Estimated, and Prioritized -, are useful for determining the quality of a PBI. The Product Backlog may begin as a large list or a short one. It may be vague or rather detailed. Typically it begins short and vague and becomes longer and more concrete as time goes on. Product Backlog Items slated for implementation soon will be ‘refined’: clarified, better refined, split into smaller chunks, as part of the Product Backlog Refinement activity.
PBIs that we plan to work on soon should be near the top of the backlog, small in size, and very detailed so that they can be worked on in a near-term Sprint. PBIs that we won’t work on for some time should be toward the bottom of the backlog, larger in size, and less detailed. That’s OK; we don’t plan to work on those PBIs any time soon. This type of organizing the work is known as Product Backlog Iceberg.
The Product Owner is responsible and accountable for maintaining the Product Backlog, although the Product Owner may – and should – have help in producing it and keeping it up to date. Product Backlog Items may originate from the Product Owner, from team members, or from other stakeholders.