HKSM
Relative Sizing/Story Points
Beyond estimating cost, story points express the relative size of a user story or feature. Teams pick a point value by judging the story holistically, taking into account uncertainty and risk, the effort likely required, and its level of complexity.
Key Points
- Story points are a relative measure of size, not hours or days; teams often use a Fibonacci-like scale (1, 2, 3, 5, 8, 13).
- Point values reflect a combined view of effort, complexity, and risk/uncertainty decided by the team.
- They enable forecasting with velocity for sprint and release planning without detailed task estimates.
- Use stable reference stories to keep sizing consistent; recalibrate only when needed.
Example
During backlog refinement, the team compares a new story, "Enable social login," to a known 3-point reference. Because it involves third-party integrations and unknown OAuth nuances, they agree it is more complex and risky, assigning 8 points. With a velocity of about 20 points per sprint, the product owner forecasts that two similar 8-point items plus a small 3-point item could likely fit in the next sprint.
PMP Example Question
Which statement best describes story points in Agile estimation?
- An absolute time estimate in hours assigned to each user story
- A relative sizing method that considers effort, complexity, and risk
- A measure of business value delivered to stakeholders
- A count of the number of tasks needed to implement a user story
Correct Answer: B — Relative sizing that considers effort, complexity, and risk
Explanation: Story points are a relative measure of size, determined by the team's assessment of effort, complexity, and risk, not a direct time estimate, business value, or task count.
