THE IVOTE GUIDE
Fibonacci Story Points: Choosing an Estimation Scale
Story points express the relative size of work as understood by a team. They can account for effort, complexity, and uncertainty. A story point is not a universal unit of time, and an eight-point story does not automatically take eight hours.
Why use the Fibonacci sequence?
The familiar scale of 1, 2, 3, 5, 8, 13, and 21 leaves larger gaps as work grows. Those gaps encourage a team to acknowledge that large, uncertain tasks cannot be estimated with fine precision. iVote also offers larger Fibonacci values for teams that use them.
Treat the numbers as relative categories rather than a mathematical promise. If a story feels much larger than your reference stories, splitting it may be more useful than debating whether it deserves the next number on the scale.
Choose reference stories your team understands
Start with a small piece of completed or well-understood work. Agree on its approximate size, then compare the next story against it. Ask whether the new story introduces more moving parts, unfamiliar work, coordination, or testing.
A good reference belongs to the team’s own context. Copying another team’s point definitions can create false precision because tools, experience, and dependencies differ. Revisit the references when the team or its work changes significantly.
Discuss uncertainty rather than hiding it in a number
When a participant chooses a question mark, ask what information is missing. The next step may be a technical investigation, clearer acceptance criteria, or a conversation with another team. Increasing the estimate alone does not make the uncertainty disappear.
During a reveal, look at the distribution as well as the summary statistics. A midpoint between a very small estimate and a very large estimate can suggest agreement where none exists. Ask participants to explain assumptions before choosing a final value.
When T-shirt sizes or hours are a better fit
T-shirt sizes such as S, M, and L can support early conversations where the team does not yet need a detailed numerical estimate. Hours may suit a discussion specifically about expected duration, provided the team is clear about what the estimate includes.
iVote supports Fibonacci, T-shirt sizes, powers of two, hours, and custom cards. Choose the deck before voting. Changing the deck clears the current votes, so finish the discussion or tell participants that you are starting a fresh round first.