Story Points in Agile Development: what, why and how?

From the archive: originally published on the Eastpoint blog on 18 April 2024. Some details reflect that time.

Story points are a unit of measure for expressing an estimate of the overall effort that will be required to fully implement a product backlog item or any other piece of work.

When used in agile software development, story points help the team estimate the work more effectively, allowing them to prioritize tasks and manage their time.

What Are Story Points?

Story points assess the effort, complexity, and risk involved in a task, rather than focusing on the hours it takes to complete.

They are a relative measure, meaning a task estimated at two story points is anticipated to take twice as much effort as a task estimated at one story point.

Story points consider various factors, including the amount of work to do, the complexity of the work, and any uncertainties or risks that might affect the progression and completion of the task.

Benefits of Using Story Points

1. Flexibility in Estimations: Story points provide flexibility as they are not tied to specific hours or days, which helps accommodate changes without re-estimating the entire schedule.
2. Improved Team Communication: Using story points forces team members to discuss features in detail, enhancing understanding and communication within the team.
3. Enhanced Forecasting: By understanding their velocity, teams can predict how much work they can handle in future iterations, which improves long-term planning.

Potential Downsides and Pitfalls

1. Misinterpretation: Story points can be misunderstood as a measure of complexity or time alone, which might lead to inaccurate estimations.
2. Inconsistency: Without a baseline, teams might apply story points inconsistently, leading to skewed data and poor forecasting.
3. Over-reliance on Velocity: Focusing too much on velocity as a performance indicator can pressure teams to inflate their estimates or compromise quality to meet targets.

How to Use Story Points Effectively

• Establishing a Baseline: Start by establishing benchmark stories that the team agrees are simple, medium, or complex. Use these as a reference to estimate new stories.
• Regular re-evaluation: Story points should be discussed and re-evaluated regularly to adapt to the team’s changing dynamics and understanding of the project. Retrospectives are a great time to do this.
• Avoid Comparisons Between Teams: Story points are team-specific and should not be used to compare productivity across different teams.

Exercises to Improve Use of Story Points

1. Planning Poker: An interactive way to make estimation a team effort. Each team member uses cards numbered to represent story points to vote on the effort required for each task. This encourages discussion and helps reach consensus.
2. Retrospectives on Estimations: Regularly review past sprints to discuss what was over or underestimated and why, which helps refine future estimations.
3. Story Point Calibration Meetings: Occasionally recalibrate your understanding of what each level of story points looks like by reviewing completed tasks.

Conclusion

When implemented thoughtfully, story points can be a powerful tool in agile development, aiding in better planning and team alignment.

By understanding and anticipating the pitfalls and actively engaging in exercises to refine the estimation process, development teams can ensure that they use story points effectively, leading to more successful project outcomes.