Definition
The product backlog is a dynamic, ordered list of everything that might be needed in a product and is the single source of requirements for any changes to be made to the product. It contains features, functions, requirements, enhancements, and fixes that constitute the changes to be made to the product in future releases. The product owner is responsible for the product backlog, including its content, availability, and ordering. This list evolves as the product and the business environment change, with items prioritized based on business value, risk, and dependencies. A well-maintained product backlog ensures that the development team is always working on the most valuable items for the customer. For example, a software company might list 'implement user profile editing' as a high-priority item. It is distinct from a sprint backlog, which is a subset of the product backlog selected for a specific iteration. The product backlog is a core concept in Agile methodologies and appears on exams like the PMI-ACP, CAPM, and PMP.