Optimizing User Story Estimation for Project Management
Now that the User Stories are complete and you’ve completed the Backlog Grooming, it’s time to dive into Development, right? Wrong. You now need to Estimate the stories in order to ensure the team, and the project, is set up for success.
Let’s explore some of the key principles and best practices for estimating user stories while highlighting common mistakes that project managers should avoid.
What’s a User Story Estimate?
A story estimate refers to the assigned value or effort estimation given to a user story during the planning phase of a project. User stories form the basis for defining and prioritizing work, and estimating these stories is a fundamental aspect of Agile planning, helping teams to allocate resources, plan iterations, and prioritize backlog items effectively.
Before estimation, it is crucial to have completed the Backlog Grooming, ensuring everyone has a clear understanding of the user story's context, acceptance criteria, and dependencies.
Estimation Methods
There are numerous methods Project managers can implement to generate the Estimate. Some of the more common methods include:
Story Points
Story points are a relative estimation technique that assigns a numerical value to represent the effort, complexity, and uncertainty of a user story.
How it works: Teams collectively assign story points to user stories based on their perceived complexity, effort, and other relevant factors. The Fibonacci sequence (1, 2, 3, 5, 8, 13, etc.) is often used to represent increasing levels of complexity. This method acknowledges the uncertainty inherent in estimating larger user stories.
Planning Poker
Planning Poker is a collaborative estimation technique where team members discuss and collectively estimate the effort or complexity of user stories.
How it works: Team members use a deck of cards with values representing story points. Each member privately selects a card indicating their estimate, and the team discusses the reasons behind their choices. Consensus is reached through discussion and, if necessary, repeated rounds.
T-shirt Sizing
T-shirt sizing is a high-level estimation technique that categorizes user stories into sizes such as small, medium, large, or extra-large.
How it works: Teams assign sizes to user stories based on their perceived relative effort or complexity. This method is useful for quick estimations during initial backlog grooming and I particularly effective for large backlogs.
Relative Sizing
Relative sizing involves comparing user stories against each other to determine their relative size or effort.
How it works: Teams evaluate user stories in relation to one another, expressing the effort required to complete each story relative to the others. This method is valuable for quick estimation during backlog refinement.
Why do we estimate Points vs Hours?
It’s important to understanding the difference between Points and Hours. Typically, these terms are associated with work items, especially user stories or tasks, and they serve distinct purposes within the Agile framework.
Points
Points is an abstract unit used to estimate the overall size, complexity, and effort required to complete a user story or task.
Given Estimation is conducted during Sprint Planning, Story Points provide a high-level understanding of the magnitude of work, representing the team's collective assessment of the relative size and complexity of a user story compared to others in the backlog. Story Points are not directly tied to specific hours but is a relative measure used for prioritization and forecasting.
Hours
Hours or Hours Remaining represent the amount of work left to complete a user story or task, measured in actual hours.
Far more granular and specific, Hours Remaining provides a real-time view of the work progress within the sprint. As the team progresses through the work, team members update the remaining hours to reflect the work remaining. This allows for a more detailed and day-to-day tracking of the team's progress.
Best Practices for User Story Estimation
Involve the Entire Team
Estimation should be a collaborative effort involving the entire development team. Combining diverse perspectives ensures a more comprehensive understanding of the user story's complexity, and in turn, provides a far more robust estimation of the Story Points to be allocated to the respective User Story.
Use Historical Data
Leveraging historical data from previous projects can enhance estimation accuracy. It provides insights into the team's velocity and the time required for similar user stories. Be sure to regularly review and analyze historical data to inform the team's estimation process. Consider past velocity, completion rates, and any lessons learned from previous sprints.
Break Down Large Stories
Large user stories are prone to inaccurate estimation. Breaking them down into smaller, more manageable tasks allows for better granularity and more accurate estimation.
Consider Dependencies
Conduct a thorough analysis of dependencies during sprint planning to ensure that the team has a comprehensive understanding of how one task or story may affect others. Identifying and understanding these dependencies helps in creating a more realistic project timeline.
Failing to identify and consider dependencies between user stories or tasks can lead to inaccurate estimates.
Common Mistakes to Avoid
Lack of Clear Acceptance Criteria
Incomplete or unclear acceptance criteria for user stories can lead to misunderstandings and inaccurate estimates. Without a clear definition of what "done" means for a particular story, team members may have differing expectations.
Ensure that user stories have well-defined and agreed-upon acceptance criteria. This clarity helps the team accurately assess the effort required to meet the specified requirements.
Underestimating Complexity
Rushed or overly optimistic estimations can result in underestimating the complexity of user stories or tasks. This often occurs when teams do not take the time to thoroughly analyze and understand the requirements.
Instead, encourage the team to take the necessary time to discuss and analyze user stories before providing estimates. Breaking down complex stories into smaller tasks can also help in achieving more accurate estimations.
Individual Biases
Estimations can be influenced by individual biases or variations in team members' skill levels. Team members may have different perspectives on the effort required for a particular task.
Promoting a collaborative estimation process (using any of the methods identified earlier), to ensure that the team collectively discusses and aligns on the estimates will mitigate individual biases and leverages the diverse expertise within the team.
Neglecting External Factors
Estimations may go wrong when teams fail to consider external factors such as interruptions, meetings, or other non-development activities that could impact available work hours. Be sure to account for external factors when estimating capacity for a sprint, recognizing that team members may not have 100% of their time dedicated to development tasks.
Achieving Project Success
Estimating user stories is a pivotal aspect of project management that requires careful consideration and collaboration. By implementing effective estimation techniques, considering historical data, and avoiding common pitfalls, project managers can enhance the accuracy of estimates and contribute to the overall success of the project.
Adopting these practices ensures that development teams and stakeholders are aligned, setting the stage for a more efficient and successful project delivery.
