HKSM
Story Point
A dimensionless unit used to estimate and compare user stories by relative effort, complexity, and uncertainty.
Key Points
- Represents relative size, not hours or days.
- Combines effort, complexity, and risk into a single value.
- Teams use a consistent scale (often Fibonacci: 1, 2, 3, 5, 8, 13).
- Enables forecasting via velocity (points completed per iteration).
Example
A Scrum team selects a reference story rated as 3 points. A similar but slightly harder story is scored as 5 points, while a small bug fix is 1 point. Over recent sprints, the team completes about 20 points per sprint, so they plan the next sprint around stories totaling close to 20 points.
PMP Example Question
Which statement best describes a story point in agile estimation?
- A fixed measure equal to one ideal developer day
- A dimensionless value expressing the relative size of a user story
- A cost-based metric used for earned value calculations
- A measure of calendar time needed to complete a task
Correct Answer: B — A dimensionless value expressing the relative size of a user story
Explanation: Story points are unit-less and compare stories by relative effort, complexity, and uncertainty, not by specific time or cost.
