One of the key elements of planning poker is the use of the fibonacci series as a scale for estimating task size. The fibonacci series is a mathematical sequence that begins with 0 and 1, and each subsequent number is the sum of the previous two numbers. The sequence looks like this: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, and so on.
So, why do we use the fibonacci series in Scrum poker?
There are several reasons why the fibonacci series is commonly used in planning poker:
- It allows for a wide range of estimates: The fibonacci series provides a wide range of values that can be used to estimate the size of a task, which allows for more precise estimates than a binary scale (e.g. small/medium/large).
- It reflects the uncertainty of estimation: The larger the task, the greater the uncertainty around the estimate. The fibonacci series reflects this uncertainty by increasing the values exponentially as the estimates get larger. For example, it is much easier to estimate that a task will take 2 days (value 2) than it is to estimate that it will take 13 days (value 13).
- It encourages discussion and consensus-building: The use of the fibonacci series encourages team members to discuss and reach a consensus on their estimates. This is because the values in the series are not evenly spaced, which can lead to discrepancies in estimates. For example, if one team member estimates a task as a value 5 and another team member estimates it as a value 8, there will be a significant difference in their estimates. This can lead to a discussion and ultimately a consensus on the appropriate estimate.
- It promotes a common language: The use of the fibonacci series provides a common language for discussing and estimating tasks, which can help to reduce misunderstandings and improve communication among team members.
Overall, the fibonacci series is a valuable tool for agile estimation techniques like planning poker because it allows for a wide range of estimates, reflects the uncertainty of estimation, encourages discussion and consensus-building, and promotes a common language for discussing tasks. By using the fibonacci series, Scrum teams can more accurately and effectively estimate the size of development tasks and prioritize their work.
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