Fibonacci Sequence Estimation #
Fibonacci Sequence Estimation is a popular technique in Agile methodologies used for estimating the effort required to complete user stories or tasks. The Fibonacci sequence (1, 2, 3, 5, 8, 13, 21, …) is used because the numbers reflect the increasing uncertainty associated with larger tasks. The gaps between numbers grow as the sequence progresses, helping teams avoid getting bogged down in fine-grained distinctions for larger, more complex tasks.
Key Characteristics of Fibonacci Sequence Estimation: #
– Relative Estimation: Focuses on comparing tasks rather than predicting exact timeframes.
– Handling Uncertainty: Larger numbers reflect higher uncertainty, making it easier to account for unknowns.
– Facilitates Discussion: Encourages team members to discuss and reach a consensus on estimates.
Steps of Fibonacci Sequence Estimation: #
1. Preparation:
– The Product Owner prepares a list of user stories to be estimated.
– Each team member receives a set of Fibonacci sequence cards (1, 2, 3, 5, 8, 13, 21, …).
2. Presentation:
– The Product Owner presents a user story to the team, explaining the requirements and acceptance criteria.
3. Discussion:
– The team discusses the user story to ensure everyone understands it. Questions and clarifications are addressed during this phase.
4. Estimation:
– Each team member privately selects a card representing their estimate for the user story’s effort or complexity.
– All team members reveal their cards simultaneously.
5. Consensus:
– If all estimates are the same, that estimate is recorded.
– If estimates vary, the team discusses the reasons for the differences. Team members with the highest and lowest estimates explain their reasoning.
– The process is repeated until a consensus is reached, or at least the estimates converge closely.
6. Recording:
– The agreed-upon estimate is recorded in the user story.
Example of Fibonacci Sequence Estimation for an E-Commerce Website #
Scenario: The team is estimating user stories for an e-commerce website project. The goal is to estimate the effort required to implement the “User Registration” feature.
Participants:
– Product Owner: Eva
– Development Team: Alice (Frontend Developer), Bob (Backend Developer), Carol (QA Engineer)
– Scrum Master: Dave
User Story:
– ID: PBI-003
– Description: As a user, I want to register an account so that I can make purchases and track orders.
– Acceptance Criteria:
– User can register with an email and password.
– Email verification is required.
– Password must meet complexity requirements.
– Registration form includes validation.
Fibonacci Sequence Estimation Session: #
1. Presentation:
– Eva (Product Owner) presents the user story PBI-003 to the team, detailing the requirements and acceptance criteria.
2. Discussion:
– The team discusses the user story.
– Alice: “The frontend form will need validation and integration with the backend.”
– Bob: “We’ll need to implement email verification and ensure password security.”
– Carol: “We should plan for comprehensive testing, including validation and security checks.”
3. Estimation:
– Each team member privately selects a Fibonacci card representing their estimate for the effort required.
– Alice selects 8, Bob selects 13, and Carol selects 8.
4. Consensus:
– The cards are revealed: 8, 13, 8.
– Bob explains his higher estimate: “Email verification and security might take more effort than initially thought.”
– Alice and Carol discuss their lower estimates, considering reuse of existing components and straightforward validation.
– After discussion, the team agrees to re-estimate.
5. Re-Estimation:
– The team members select their cards again.
– This time, Alice selects 8, Bob selects 8, and Carol selects 8.
6. Recording:
– The consensus estimate of 8 story points is recorded for user story PBI-003.
Summary of Fibonacci Sequence Estimation: #
| User Story ID | Description | Estimate (Story Points) |
| PBI-003 | User Registration | 8 |
Benefits of Fibonacci Sequence Estimation: #
– Relative Accuracy: Provides a more accurate reflection of effort and complexity by comparing tasks.
– Manages Uncertainty: Larger gaps between numbers in the sequence help account for increasing uncertainty in larger tasks.
– Promotes Team Discussion: Encourages detailed discussion and consensus-building within the team.
– Avoids Over-Precision: Helps avoid the false precision of estimating larger tasks with small units.
Conclusion #
Fibonacci Sequence Estimation is an effective technique in Agile for estimating the effort and complexity of user stories or tasks. By using the Fibonacci sequence, teams can manage uncertainty, encourage discussion, and achieve more accurate and realistic estimates. The example of estimating the “User Registration” feature for an e-commerce website demonstrates how this method facilitates informed decision-making and consensus-building within the team.
