What are the Time-Boxes in Large-Scale Scrum (LeSS) Product Backlog Refinements (PBR) session?

Question

We've turned from Scrum to the basic LeSS Framework for scaling Scrum beyond a single team.

In product Backlog Refinement article, 3 types of Refinement have been introduced which are as follows:

1. Overall Product Backlog Refinement (4 hours)
2. Team-level Product Backlog Refinement
3. Multi-team Product Backlog Refinement

At the LeSS meetings section of this page mentioned 4 hours duration for Overall Product Backlog Refinement (PBR). But I couldn't see anything about the duration of the other two Refinements.

I'd like to know what are the Time-Boxes on a team and multi-team level Refinement?

Answer 1

5-10% of a Sprint:

This is somewhat consistent with the Scrum Guide, which states:

Refinement usually consumes no more than 10% of the capacity of the Development Team.

However, in Scrum, that is not typically seen as a timebox. Sometimes, teams will spend more time refining. Othertimes, they may take on less. I recently responded to a question on the Scrum.org forums about estimating Spikes where I tried to make this point - identifying Spikes in the backlog are one method of planning and accounting for refinement and if there's a lot of research, investigation, and learning, the team members may spend more than 10% of their capacity trying to refine Product Backlog Items.

The other thing to consider is that LeSS elevates refinement to events, where Scrum just has it as something that happens and leaves it as an exercise to the team to determine how. I believe that having refinement meetings are valuable, but refinement can (and should) happen outside of the meetings.