What is Relative Estimation: Agile Estimation Techniques Explained
In agile projects, accurate estimation is key. Unlike traditional methods, agile teams use relative estimation to judge the size of tasks or user stories by comparing them to others. This technique helps in managing the product backlog and assigning story points effectively.
Approaches like Planning Poker allow the scrum team, including the scrum master and product owner, to collaborate on estimates. Relative estimation benefits agile teams by providing a consistent and reliable way to understand and estimate backlog items.
Overall, relative estimation in agile simplifies the estimation process and improves the accuracy of planning in software development.
What is Relative Estimation?
Relative estimation is the process where tasks or user stories are evaluated by comparing them to a reference story, rather than assigning absolute values. This method helps agile teams quickly gauge the size and effort needed for various tasks.
First, the team aligns on a reference user story, such as a simple login feature, and assigns it a story point value. Other tasks are then estimated relative to this benchmark. For example, if developing a comprehensive reporting feature is more than three times as complex as the login feature, it might receive a story point value of 13. Conversely, a minor UI adjustment might be considered half as complex and get a value of 2.
This approach helps the scrum team, including the scrum master and product owner, discuss and understand the relative effort for each task. It ensures a more consistent and transparent estimation process, crucial for effective agile estimating in software development.
Why Estimate User Stories Relatively to Each Other
Relative estimation helps to manage your product backlog in different ways:
- Improved Accuracy: By comparing tasks to each other, relative estimates helps agile teams to make more accurate predictions about the effort required.
- Enhanced Collaboration: Techniques like Planning Poker encourage the scrum team, including the scrum master and product owner, to engage in discussions and reach consensus on estimates.
- Consistency and Comprehensibility: Using a relative scale, such as the Fibonacci sequence, ensures consistent estimates and makes the process more understandable to stakeholders, as tasks are compared to each other, not estimated in every last detail.
- Transparency: It provides a clear view of how different backlog items stack up against each other, which is useful for stakeholders.
- Better Planning: With more accurate and consistent estimates, agile teams can better plan their sprints and manage the amount of work effectively.
Absolute vs. Relative Estimation
In agile, there are two main approaches to estimating work: absolute size estimation and relative size estimation.
Absolute Estimation
Absolute estimation involves assigning a specific numerical value to each task or user story based on its perceived effort and complexity. For instance, a team might estimate that a feature requires 20 hours to complete. While this method provides a straightforward estimate, it has its drawbacks. Estimating time or effort precisely can be challenging and often leads to inaccuracies. Different team members might have varying opinions on how much effort a task will require, causing inconsistency.
Relative Estimation
Relative estimation compares tasks to each other rather than assigning absolute values. This technique allows teams to judge tasks based on their complexity relative to a known baseline or reference story. For example, if a login feature is considered a medium complexity (5 story points), a more complex reporting feature might be given a higher value, such as 13 points.
- Accuracy: Relative estimation tends to be more accurate over time as teams better understand their capabilities and adjust their reference points.
- Ease of Understanding: Absolute values can be hard to pin down, whereas comparing to a known reference makes relative estimation easier to grasp.
- Consistency: Relative estimation promotes uniformity within the team's estimates by providing a common baseline.
- Adaptability: In fast-paced agile projects, relative sizes can be quickly adjusted as team dynamics and project requirements change.
Overall, while both methods have their uses, relative estimation is typically more effective for agile teams to manage their product backlog and plan their work efficiently.
Agile Estimation Techniques
Agile teams use various estimation techniques to improve planning and management of their product backlog. Three popular methods are Planning Poker, Affinity Estimation, and Dot Voting.
Planning Poker
Planning Poker is a well-known technique where team members use cards to independently estimate the effort required for a task. Each card represents a Fibonacci sequence number, and the secretive nature of the estimates promotes independent thinking and lively discussion.
For online sessions, you can use the web app here to facilitate Planning Poker.
For offline sessions, you can download and print the card PDF from the same link.
Affinity Estimation
Affinity Estimation is a quick and intuitive way for teams to group similar-sized tasks together. The team places user stories on a board and moves them around based on their perceived size and complexity relative to each other. This method is useful for quickly establishing a high-level overview of the product backlog.
For more information on Affinity Estimation, please check my detailed blog post here.
Dot Voting
Dot Voting is a simple and democratic estimation technique. Team members distribute dots or points among tasks they believe are important or require attention. This visual method helps prioritize tasks effectively and ensures everyone’s input is considered.
For an in-depth guide to Dot Voting, please refer to my blog post here.
