Concepts
Agile Sizing and Estimation is a crucial aspect of Agile project management, which is comprehensively covered in the PMI Agile Certified Practitioner (PMI-ACP) exam.
Understanding Agile Sizing and Estimation Methods
Agile estimation is used to assess the size, duration, and complexity of developing specific user stories, features, or other items in Agile software development environments. But, unlike traditional project management methods, agile teams use relative measures rather than absolute metrics to estimate the work effort.
Agile teams typically use two methods to estimate necessary work effort – Story Points and Ideal Days.
- Story Points (SP): SP is a technique based on the comparative complexity of work. It considers not just the amount of work but also the degree of uncertainty and risk in the work.
- Ideal Days (ID): ID is a scenario where the team only works on the project at hand without any interruptions. It specifically mentions how much time it would take to complete one user story without any mountains.
The primary reason to use these relative measurement units is to avoid a scenario where the team would stall by trying to estimate absolute metrics, as it’s hard to know precisely how much time a specific task will take.
Why is Agile Sizing and Estimation Important?
Agile estimating methods are significant due to the following reasons:
- Planning: Estimating the size of work items is an integral part of release and iteration planning, reinforcing the connection between planning and estimation.
- Resource Allocation: By estimating the size of work, teams can better allocate resources and foresee possible bottlenecks in terms of availability of team members with specific skills.
- Progress Tracking: Agile teams can track progress towards goals and compare estimated and actuals to gain insights into how well they are performing and where improvements are needed.
- Risk Management: Estimating provides an opportunity to identify and discuss potential risks, which encourages teams to discuss and solve issues early.
Let’s understand with an example, suppose we have three user stories to be estimated. In story points, if Story A is given three points and Story B is given eight points, this doesn’t mean Story B will take more than double the time of Story A, rather it means that Story B is more complex in comparison to Story A. These points can then be used to calculate velocity of an Agile team.
Velocity Calculation
A team’s velocity is the total effort estimate (story points, ideal days, etc.) of user stories completed in an iteration or sprint.
For instance, if in the first iteration, the team completes user stories with a total estimation of 24 story points, and in the second iteration completes user stories with a total estimation of 28, the team’s average velocity is 26 ((24+28)/2)
Practices to Improve Agile Sizing and Estimation:
- Estimation should be completed by the team: As the team will be performing the work, they are best positioned to provide the estimation.
- Refine Estimations: Estimations should be refined regularly as the team gains more knowledge and understanding of the tasks.
- Use historical data: Past performance is an excellent predictor of future performance. Look at the team’s past velocity and use it as a benchmark for future sprints.
- Defer Decisions: Agile encourages deferment of decisions until the last responsible moment. This is true for estimation as well. Don’t estimate too far ahead as requirements and circumstances might change.
In conclusion, Agile Sizing and Estimation is a fundamental technique in Agile project management best practices. It helps Agile teams plan, monitor and adapt, which are all crucial for the PMI-ACP exam.
Answer the Questions in Comment Section
True or False: In Agile, team velocity is a measure of the amount of work a team can handle during a single sprint.
- True
- False
Answer: True.
Explanation: Velocity is a measure of the average amount of product backlog turned into an increment of product during a sprint by an Agile Team, tracked by the Development Team for planning and process improvement.
Story points are a measure of the complexity of work to be done, not the time it will take to complete. True or False?
- True
- False
Answer: True.
Explanation: 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.
Which of the following is NOT a common Agile estimation technique?
- A. Planning Poker
- B. T-shirt sizes
- C. Fibonacci sequence
- D. Waterfall method
Answer: D. Waterfall method.
Explanation: The Waterfall method is a sequential design process, often used in software development processes, where progress is seen as flowing steadily downwards like a waterfall through several phases. This is in contrast to Agile methods which are iterative.
In Agile projects, estimates are often given in terms of:
- A. Hours and minutes
- B. Weeks and days
- C. Story points and ideal days
- D. Months and years
Answer: C. Story points and ideal days.
Explanation: Agile projects prefer to use story points and ideal days for estimation as they better represent the complexity and size of the work to be done.
True or False: In Agile, it is recommended to use only one sizing method for all types of tasks.
- True
- False
Answer: False.
Explanation: Different tasks may require different sizing approaches. Some tasks might be better estimated with story points, others with ideal days, depending on the nature, complexity, and scope of the work.
In Agile, it is advised to refine estimates:
- A. As the team gains more knowledge
- B. Every sprint
- C. Once a month
- D. Never
Answer: A. As the team gains more knowledge.
Explanation: Agile promotes the refinement of estimates as more information becomes available and as the team gets more clarity on the work to be done.
The larger the story, the more likely the estimate is inaccurate. True or False?
- True
- False
Answer: True.
Explanation: Larger stories have more ambiguity and are thus harder to estimate accurately. They are often broken down into smaller stories for better estimation.
The Ideal time used in Agile is the amount of time something takes when it goes perfectly. True or False?
- True
- False
Answer: True.
Explanation: The ideal time is used in Agile as a measure to estimate how much time a task would take without any interruptions.
After several sprints, a team’s velocity is expected to:
- A. Increase
- B. Decrease
- C. Stay the same
- D. Fluctuate
Answer: D. Fluctuate.
Explanation: A team’s velocity may fluctuate based on a variety of factors including changes in team composition, complexity of work, and other factors.
Estimation in Agile is a collaborative process involving the whole team. True or False?
- True
- False
Answer: True.
Explanation: Unlike traditional project management, in Agile the entire team is involved in the process of estimation, bringing different perspectives and expertise to the table.
Which of the following Agile estimation techniques is based on consensus?
- A. Planning Poker
- B. Ideal Time
- C. Fibonacci sequence
- D. T-Shirt Sizes
Answer: A. Planning Poker.
Explanation: Planning Poker is a consensus-based estimation technique for Agile teams. Each team member provides their estimate, and the estimates are then discussed until consensus is reached.
In Agile Estimation, the no-estimate approach suggests that:
- A. Estimations are not necessary in Agile
- B. Only large story items need estimation
- C. Estimations should be done just in time
- D. Tasks should be similarly sized to need no estimation
Answer: D. Tasks should be similarly sized to need no estimation.
Explanation: The no-estimates approach proposes to work on small chunks of functionalities that don’t need a formal estimation process. The tasks are broken down so they are roughly the same size.
This blog post on Agile Sizing and Estimation really helped me understand the nuances for the PMI-ACP exam. Thanks!
Can anyone explain the difference between story points and ideal days in agile estimation?
I appreciate the breakdown of Planning Poker; it’s so useful for team alignment!
For the exam, should I focus more on understanding Fibonacci sequence in story pointing?
The information about velocity tracking was really insightful!
I think the blog missed out on the important topic of t-shirt sizing. It’s equally important in agile estimation.
What’s the best way to handle discrepancies in team member estimates?
Thanks for such an informative post!