HKSM

In this step, the Product Owner refines and clarifies each User Story so the Scrum Master and Scrum Team can collaboratively estimate the effort needed to build the functionality the story describes.

Key Points

• Product Owner clarifies objectives, acceptance criteria, and constraints for each User Story.
• Scrum Team collaborates to size effort, complexity, and uncertainty; the Scrum Master facilitates.
• Common sizing approaches include story points, T-shirt sizing, and Planning Poker.
• Results may include splitting oversized stories and updating the Product Backlog for forecasting and planning.

Example

During backlog refinement, the Product Owner explains a "Reset Password" User Story and clarifies acceptance criteria such as email verification and link expiration. After questions, the Scrum Team agrees it is a 5-point story. A related "2FA reset" scope is deemed too large and is split into a separate story for later estimation.

PMP Example Question

Which activity best represents the Estimate User Stories process in Scrum?

1. The Scrum Master assigns tasks to team members based on capacity.
2. The Product Owner clarifies acceptance criteria while the Scrum Team collaboratively sizes each story.
3. The project manager calculates earned value metrics for the sprint.
4. The team decomposes stories into tasks during the Daily Scrum.

Correct Answer: B — Clarifying stories and collaboratively estimating effort

Explanation: Estimate User Stories focuses on the Product Owner clarifying the stories so the Scrum Team, facilitated by the Scrum Master, can estimate the effort to deliver each one.