Synopsis

The Product Owner reviews the Product Vision with the team and they update the Product Vision, as needed. The team then refines the Product Backlog to ensure that they all have an up-to-date ranked list on which to base their Release Planning.

Value 

Product Backlog refinement ensures that the team focuses on capabilities that provide the most value for the investment. Higher ordered Product Backlog items (those at the top of the ranking) are better understood, testable, and sized. Initial refinement of the Product Backlog is followed by continuous refinement throughout the sprints (Product Backlog refinement should consume about 10% of the team’s time).

Note: The Scrum guide does not specify how often this task is performed, or whether it is done with meetings. We take the approach that the Product Owner will call meetings as required.

Steps

1. Review the product vision

The Product Owner and the development team review the Product Vision to align their work with the key needs and objectives.

2. Perform coarse business prioritization

The Product Owner uses a variant of the MoSCoW categorization scheme (Must Should Could Would) to identify stories that are high priority ("Must" and "Should") for the next release.

3. Detail high priority stories

The Product Owner adds detail to each "Must" and "Should" story, and the Epics containing those stories.  There should be sufficient detail to enable the team to size the story.

4. Estimate high priority stories

The development team estimates the size of the "Must" and "Should" stories, soliciting additional details from the Product Owner as needed. See Agile Estimation.

Estimating all the "Must" and "Should" stories for each Epic is generally easier than skipping from one Epic to another.

The team may discover that there are far too many high priority stories for the next release.  Rather than estimate all of the stories, the team can discuss with the Product Owner the possibility of moving some stories to a lower priority ("Could" or "Would").

5. Rank the high priority stories

The Product Owner ranks the "Must" and "Should" stories.

6. Determine if the backlog is sufficiently refined

The Scrum Master determines if the backlog is sufficiently refined.  There should be more stories ranked and sized than can fit in the next release. If this is not obvious, then continue ranking and sizing lower priority stories.

If there have been previous releases or iterations, it may be helpful to examine the team's historical velocity.