Story points estimation in SCRUM
4 min read
Story point estimation is a method used in the Scrum software development process to estimate the relative size and complexity of a user story. User stories are brief descriptions of a desired functionality or feature from the perspective of the end user. In Scrum, teams use story points to estimate how long it will take to complete a user story, as well as to compare the relative size and complexity of different stories.
To estimate a user story using story points, teams typically use a point scale, such as the Fibonacci sequence (1, 2, 3, 5, 8, 13, etc.), to assign a numerical value to each story. The values in the scale represent the relative size and complexity of the user story, with higher numbers indicating larger and more complex stories. The team will then discuss and agree on the appropriate story point value for each user story.
The benefits of story point estimation in the Scrum process include:
Providing a common language and understanding for team members: By using a standard scale for story point estimation, all team members can understand the relative size and complexity of user stories. This can help improve communication and collaboration within the team.
Allowing for more accurate forecasting and planning: By estimating the relative size and complexity of user stories, teams can more accurately forecast the amount of work they can complete in a given time period. This can help with planning and prioritization of work.
Improving transparency and accountability: Story point estimation can help make the team's progress and productivity more transparent, as it provides a common metric for measuring the amount of work completed. This can help improve accountability within the team.
Some challenges and drawbacks of story point estimation in the Scrum process include:
Subjectivity and bias: The process of assigning points to user stories can be subjective and may be influenced by personal biases. This can lead to inconsistency and disagreement within the team.
Loss of focus on the user's needs: By focusing on estimating the size and complexity of user stories, teams may lose sight of the user's needs and goals. This can lead to a lack of alignment between the team's work and the user's expectations.
Misuse and over-reliance on points: Teams may misuse or over-rely on points, using them as a measure of individual or team performance rather than as a tool for forecasting and planning. This can lead to unhealthy competition and a lack of focus on the team's goals.
Pointing poker is a tool that teams can use to estimate story points. It is a collaborative, game-like method for teams to estimate the effort required for user stories. In pointing poker, each team member is given a deck of cards with numbers on them, representing different levels of effort. The team discusses the user story and each member privately selects a card to represent their estimate. The cards are then revealed, and the team discusses any differences in the estimates and reaches a consensus on the final estimate.
Using pointing poker for story point estimation has several advantages. First, it is a collaborative process, which helps to ensure that all team members have a shared understanding of the user story and the effort required to complete it. Second, it can help to reduce bias and ensure that estimates are based on objective criteria, rather than individual opinions. Third, it is a quick and efficient way to estimate story points, which can help teams to plan and prioritize their work effectively. Overall, pointing poker is a useful tool for teams that use Scrum to manage their projects.
One common anti-pattern in story point estimation is the use of a linear scale, where each story point represents a fixed amount of time or effort. This can be problematic because it ignores the inherent uncertainty and variability in software development, and can lead to unrealistic expectations and inaccurate estimates.
Another common anti-pattern is the use of velocities, which are the average number of story points completed in a sprint. This can be problematic because it can create pressure on teams to consistently deliver the same amount of work each sprint, which can lead to suboptimal decision making and reduced flexibility.
"Estimation is neither good or bad. If you can work effectively without estimation, then go ahead and do without it. If you think you need some estimates, then make sure you understand their role in decision making. If they are going to affect significant decisions then go ahead and make the best estimates you can. Above all be wary of anyone who tells you they are always needed, or never needed."
- Martin Fowler
Overall, it's important for teams to use story point estimation in a way that accurately reflects the inherent uncertainty and variability in software development, and to avoid common anti-patterns that can lead to unrealistic expectations and inaccurate estimates.
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