Who Is Responsible for Sizing the Product Backlog Items? Understanding Scrum Roles (+ Feature's Limitation Investigation Template)

In Scrum teams, who is responsible for sizing the product backlog items is a question that often causes confusion. The Development Team holds this responsibility. They estimate the effort required for each backlog item because they're the ones building the product. The Product Owner can provide context and priorities, but sizing belongs to the developers who understand the technical complexity involved.

What Is a Product Backlog and Why Sizing Matters

A product backlog is a prioritized list of features, fixes, and technical work needed for your product. It serves as the single source of truth for what your team will build.

Sizing helps your team plan sprints and forecast delivery dates. Without accurate estimates, you can't predict how much work fits into a sprint or when features will ship to users.

The Development Team's Role in Sizing

Your Development Team sizes backlog items during refinement sessions. They analyze each item's technical requirements, dependencies, and potential challenges.

Common sizing methods include story points, t-shirt sizes, or ideal hours. The team chooses what works best for their context. For website development projects, you might estimate based on similar features you've built before.

The key is that the people doing the work provide the estimates. They know the codebase, understand the design constraints, and can spot technical risks others might miss.

Who Is Responsible for Ordering the Product Backlog

While the Development Team sizes items, the Product Owner handles ordering. They arrange backlog items based on business value, user needs, and strategic goals.

This separation makes sense. Developers know how long something takes to build. Product Owners know what delivers the most value to users and the business.

For a website redesign, your Product Owner might prioritize mobile responsiveness over a new feature because analytics show most traffic comes from phones.

Feature Limitation Investigation Template

When sizing reveals an item is too large, use this template to investigate:

• Define the feature scope: Write down exactly what the feature does and doesn't include
• Identify dependencies: List other features, APIs, or systems this work relies on
• Break into smaller pieces: Split the work into vertical slices that each deliver user value
• Note technical constraints: Document browser compatibility, performance requirements, or design system limitations
• Estimate each piece separately: Size the smaller chunks to validate your breakdown makes sense

Making Sizing Work for Your Team

Regular refinement sessions keep your backlog ready for sprint planning. Schedule these meetings at least once per sprint with your full Development Team.

Your Product Owner should attend to answer questions about requirements and user needs. The Scrum Master helps facilitate but doesn't influence sizing decisions.

Remember that estimates aren't commitments. They're your team's best guess based on current information. As you learn more during development, it's normal to adjust your understanding of an item's size.