Product Backlog refinement: owner & activity

Question

I am trying to learn Scrum, and these are some question I have:

1. Estimating the size of Product Backlog items can be considered as a Product Backlog refinement activity?

2. Who is accountable for Product Backlog refinement ?

Thank you for your answers

Answer 1

Estimating the size of Product Backlog items can be considered as a Product Backlog refinement activity?

If your team estimates, then yes, estimation or sizing Product Backlog Items would be a Product Backlog Refinement activity. Scrum doesn't mandate any particular attributes for Product Backlog Items nor the act of estimation. Refinement moves a Product Backlog Item closer to being ready for selection at Sprint Planning, and the only mandated criteria for being ready is that the Product Backlog Item can be done within one Sprint.

Who is accountable for Product Backlog refinement ?

Everyone on the Scrum Team. However, the primary actors in refinement are the Product Owner and the Developers, and these people have the most interest in making sure that refinement happens and happens well.

The Product Owner is accountable for creating and communicating Product Backlog Items, and refinement is the opportunity for everyone on the team to come to a shared understanding of what the item means. Developers are accountable for planning the Sprint, and refinement activities make sure that the team has a sufficient understanding of the work in order to plan it and then carry it out. The Scrum Master helps the team to focus on create high-value increments, and well-refined Product Backlog Items help the stakeholders to understand what the team is working on, the Product Owner to be able to effectively order the Product Backlog, and the Developers to plan and execute a Sprint.

Answer 2

The refinement is an activity performed together by everyone in the team. The Product Owner is, well, the owner of the product, but they can't really build the product by themselves without the team.

For the team to understand what needs to be built they need to communicate with the Product Owner (in Agile practices, product backlog items are not requirements or specification documents that can be handed to developers, like in traditional project management). A lot of that communication is around the refinement activity:

Product Backlog refinement is the act of breaking down and further defining Product Backlog items into smaller more precise items

The purpose is for everyone to get common understanding of what needs to be built. Once the product backlog items are split into a size the team considers appropriate, it's said that they are "ready", ready to be worked on. This often also includes an estimation from the team (at least for the items in the top of the backlog. As you go down in the backlog, items become larger, lack details and lack estimates, in other words they are not "ready" to be worked on and need to be further refined). The estimate may further be refined during sprint planning, but estimating is something that can be done as part of product backlog refinement also.

Answer 3

Estimation is considered a backlog refinement activity or alternatively it can be left until Sprint Planning or not done at all (some teams prefer not to record estimates). The advantage of preparing estimates as a refinement activity throughout the sprint is that doing so can save time during sprint planning. If the required backlog items are prioritised, estimated and sufficiently detailed in advance of sprint planning then the planning meeting itself may be kept very short.

The team as a whole are responsible for refinement but the developers alone are responsible for estimates. The PO shouldn't make estimates unless the PO is also a developer on the team.