The acronym DEEP helps to remember a widely accepted set of criteria, or checklist, to assess the quality of the Product Backlog.
Estimation and slicing of items in the Product Backlog into smaller pieces is an important factor in getting work done in a short timeframe: "Deliver [work] frequently ... with a preference to the shorter timescale."
In backlog refinement:
Backlog items should be written to a sufficient level of detail to enable the team to start work on them. They are not, in this way, similar to traditional requirements documentation. Requirements documentation is done to the level that (a) business stakeholders can agree (and sign-off) on what they will get, and (b) indicate a complete solution, prior to any work being done.
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