Backlog

What is a Backlog?

A backlog is a continuously updated collection of work items that still need to be completed. These entries can take various forms, such as business requirements, user stories, or functional descriptions of individual features. Backlogs are particularly common in agile approaches such as Scrum or Kanban.

The term “Backlog” can generally be understood as an open inventory of tasks. This way of working makes it possible for planning and execution in agile project management to take place partly in parallel rather than being strictly separated.

In this context, the backlog serves as a structuring element: the tasks it contains are prioritized according to their importance and processed step by step, often in fixed time-boxed iterations. This allows a team to deliver functional results continuously while still meeting agreed deadlines and budget constraints.

Types of Backlogs

In agile methodologies, different types of backlogs exist, depending on the framework used and the size of the organization.

In the Scrum framework, two central backlogs are distinguished. The Product Backlog represents the entire planned scope of functionality and value of a product from the user’s perspective and serves as the overarching basis for development. From this, a Sprint Backlog is derived for a defined iteration period and is jointly defined by the Product Owner and the development team. It describes the concrete scope of work for a single sprint.

In large-scale development environments involving multiple teams, such as those defined by the Scaled Agile Framework (SAFe), the backlog structure is further differentiated. A multi-level backlog model is used:

• The Team Backlog contains implementation-ready work items for individual teams and functionally corresponds to the classic Product Backlog.
• The Program Backlog is used at the program level and supports product management in steering and prioritizing the product lifecycle.
• The Solution Backlog consolidates cross-cutting solution approaches, technical enablers, or components required to implement the Program Backlog.
• The Portfolio Backlog includes approved and conceptually defined epics that are strategically relevant but not yet in active execution.

Which backlog structure is appropriate depends largely on the organizational context. In environments with multiple development teams, dividing work into team-specific backlogs helps clearly separate responsibilities. If all participants work within a single team, a central backlog may be sufficient and can also serve as the basis for release planning.

What Are Backlog Items?

Backlogs contain different types of entries, known as backlog items. These may include, for example:

• User story
• Epic
• Job story
• Functional requirements
• Quality requirements
• Use case
• Defect (bugs and errors)
• Impediment

Ideally, each item includes a description, a priority, an effort estimate, and a statement of customer value. The higher the priority of an item, the more detailed its specification tends to be in practice. At the same time, higher priority increases the likelihood that the item will be addressed and implemented.

Benefits and Objectives

Using a backlog helps teams and organizations to:

• make work items transparent,
• set priorities in a clear and traceable way,
• better manage scope, time, and budget, and
• ensure delivery capability despite changing requirements.

As a result, the backlog makes a significant contribution to the predictability and quality of outcomes.

Distinction from Related Concepts

A backlog differs from traditional project plans or task lists due to its dynamic nature. While project plans usually reflect fixed timelines and sequences, a backlog remains deliberately open to change. Unlike a simple to-do list, a backlog is prioritized and strategically aligned.