Nexus Refinement meetings and estimates
I have a question concerning refinement meetings and estimates in Scaled Scrum with Nexus.
The Nexus guide mentions many levels of refinement and give some details for a so called
"cross team refinement" (decompose items to identify team, what sequence, identify dependencies).
Estimates are not mentioned there.
In "single-team scrum" I use the refinement meeting also for estimates as mentioned in the Scrum guide.
How to do in Nexus?
Following approaches spring to my mind:
- Also do the estimates in the cross-team refinement, but then the estimation is not be done by those, who will implement the feature and it seems to be a "push-estimation"
- Do the estimates in a separate refinement with the identified team, who will most probably implement that feature
- decompose the items so much, that an estimate is not longer necessary (no-estimates approach)
What do you think about that?
The Nexus frame work from my understanding is to primarily reduce dependency and identify which team are in good place to pick a peace of work and deliver increment incrementally. Hence estimation comes when team reach this place and the same can be estimated by the right individuals.
There are many levels of refinement in a Nexus, and to an extent each of the approaches you outline can play a part:
- It is reasonable to make initial high level estimates, and then forecast which team will deliver which Product Backlog items. Note that teams should collaborate in a Nexus, there is no reason or justification for any estimate to be pushed. A Nexus is not a controlling authority which exerts push.
- The respective teams may then estimate the work they are forecasting to do at a finer-grained level. Note that a Product Backlog can be designed in such a way that candidate teams are correlated to items. As the Scrum Guide says, "Multiple Scrum Teams often work together on the same product. One Product Backlog is used to describe the upcoming work on the product. A Product Backlog attribute that groups items may then be employed."
- It's also reasonable for teams in a Nexus to break work down into items of broadly comparable sizes, if they believe it makes sense to do so. This is a valid sizing approach in Scrum.
In a company applying Nexus for which I've been working for did a Nexus Product Backlog Refinement with representatives of all teams involved. There we discussed large backlog items (calling them epics), estimating them with shirt size (S,M,L,XL) and assigning them to teams. While those epics were decomposed into smaller stories by PO and team, they got estimated in story points. If during estimation a team learns that some stories of an epic may have critical dependencies to stories or epics assigned to another team or that the epic is too large to be done in one single sprint according to the story point estimates of the decomposed stories, adjustments the the overall plan were made before sprint planning, changing team-assignment or sprint-assignment of backlog items causing problems.
Steven, that is exact what I am doing. Rough estimation in the cross-team refinement, story point estimation in the team after the stories have been assigned.
Thank you all for your opinions.
Thank you for this clarification.