In the Scrum view of the world, the Product Owner (PO) has accountability for the Product Backlog.  This includes the responsibility for the Product Backlog items to be clearly expressed, and be in the right order.  I’ve had the opportunity to work with several companies where the PO was located remotely from the Scrum teams – and in a few cases the POs weren’t even on the same continent as their Scrum teams.  Development can be slowed down a lot if the Scrum team can’t get timely answers to questions, so having a PO who is offset in time, or overloaded and hard to reach, can create problems.

I’ve found that having a good Business Analyst (BA) co-located with the Scrum team can really help things run smoothly.  If the BA and the PO have a close working relationship, the BA can assist the PO in running the backlog and getting the requirements right.

Bill Wake created the INVEST acronym to describe characteristics of a good user story, where INVEST stands for:

• I – Independent: we would like user stories to not overlap in concept, and we would like to able to schedule and implement them in any order
• N – Negotiable: not an explicit contract for features; a good story captures the essence, not the details
• V – Valuable: needs to be valuable to the customer
• E – Estimable: development teams need to be able to estimate the work for a given user story; not an exact estimate, but enough to rank and schedule; a story that is hard to estimate may need to be broken down further
• S – Small: good stories tend to be small
• T – Testable: a good story is testable

(https://xp123.com/articles/invest-in-good-stories-and-smart-tasks)

If we think about the PO and BA working together on getting the stories right, you can see that there can be a division of who focuses on what in their working relationship.  The PO, for example, might have the BA take on the primary responsibility for making sure the stories are Estimable, Small, and Testable.  The PO could have the primary responsibility of ensuring the stories are Valuable and Negotiable.  Both of them could take care that the stories are Independent.  If we look at this example using a “slider” graphic, it might look like this:

Another PO and BA pair might have the BA more responsible for Negotiable, so that slider could be moved to the right.  I’ve seen examples where the PO wanted the BA to do all the handling of the Scrum team and backlog, and that group did fine with that arrangement.  I’ve also seen the opposite case, and lots of variations in between.  There isn’t a “one size fits all” answer, which is why it’s important for the PO and BA to figure out who has primary responsibility for what.