Preface of the series

The series of “Essence of Scrum” articles tries to identify the essence of Scrum elements (e.g., events and artifacts) so that:

  • the core can be understood without much effort.

  • the feeling overwhelmed can be reduced.

  • the gradual adoption is more possible.

My selection and elaboration of “essence” is very subjective. Follow the advice at your own risk.

Main references for the whole series:


The first article discusses the Product Backlog Refinement (PBR).

In a nutshell

Product backlog refinement (PBR) is a Scrum event in which the Scrum Team properly orders and breaks down Product Backlog so that the Developers feel confident enough about the top Product Backlog Items to take them into a Sprint .



  • A Product Backlog that is both ordered1 and granularity gradient2:

    • Is ordered according to product roadmap and expectations of stakeholders.

    • Is granularity gradient according to confidence of the Scrum Team .


  • A Product Backlog that has the property of ODDE (ordered, dynamic, detailed appropriate, and estimated)3.

  • The top Product Backlog Items meet the Definition of Ready criteria4 defined and evolved by the Scrum Team .



  • Strategy breakdown (e.g., product roadmap, OKR, OGSM, impact mapping, user story mapping).

  • A Product Backlog that is roughly ordered according to product roadmap and expectations of stakeholders.

Tools and Techniques


  • Short-term strategic planning statements in brief

  • Logical approach to ordering items

  • Logical approach to breaking down items

  • Estimation in proper granularity5


  • SPIDR (Spike, Paths, Interfaces, Data, and Rules)6

  • Techniques for enabling specification7

  • Encouraging participative decision-making in proposal and ordering of Product Backlog Items



'Essence of Scrum' Series

❶ Product Backlog Refinement

Daily Scrum

Sprint Planning

Sprint Review

Agile Success Recipes: Example Agendas for Efficient Scrum Ceremonies


2020-11-24 Memo

The series of articles have been updated according to the 2020 revision of The Scrum Guide (published on Nov 2020).

  1. “Priority” is the term used in the Scrum Guide 2010: “Product Backlog is sorted in order of priority” (p.6).    But the term was changed to “order” in 2011: “Product Backlog management includes: […] Ordering the items in the Product Backlog to best achieve goals and missions” (p.5).    See the article “Ordered Not Prioritized” for more details. ↩︎

  2. The Scrum Guide 2017 says: “Higher ordered Product Backlog items are usually clearer and more detailed than lower ordered ones. More precise estimates are made based on the greater clarity and increased detail; the lower the order, the less detail” (p.15).    See “Granularity Gradient” for more details. ↩︎

  3. Daniel Teng proposed the ODDE properties (ordered, dynamic, detailed appropriate, and estimated) for product backlog. See the article “ODDE 的 Product Backlog” (in Chinese) for more details. ↩︎

  4. Definition of Ready ↩︎

  5. Mike Cohn discusses different levels of estimation activities in his article “Why Agile Teams Should Estimate at Two Different Levels.” ↩︎

  6. Mike Cohn proposed the SPIDR approach (spike, paths, interfaces, data, and rules) for breaking down user stories. Watch the “Stop Wasting Time Splitting Stories” video for more details. ↩︎

  7. Enabling specification ↩︎