Many have asked why Fibonacci series is used for the story point estimates. Though I agree, it is not the only way to estimate based on relative sizing and many of them use different methods, Fibonacci sequence is used frequently.
In this article, I would like to help you to get a better understanding of the fundamentals behind using the Fibonacci series. And you won’t even need a deck of cards for this one.
Example Fibonacci sequence – estimated effort
Let’s take a Fibonacci Scale example where you are asked to hold a weight of 2 Kgs.
If the weight is increased by .02 Kgs (i.e. 2.02 Kgs is the total weight), it would be very negligible to notice the difference by the person who lifts the weight especially when they are unaware that it was increased by 0.02 Kgs.
The same is true when a person is asked to lift the weight of 5 Kgs and then it is increased by 0.05 Kgs without them noticing, the person wouldn’t feel the increase in the weight.
Weber in 1834 realised that there is a particular threshold and the ratio, the background intensity to the incremental threshold, is relatively constant.
In the equation, K is constant.
ΔI = IK
Coming back to Fibonacci sequence in this series of numbers, an accurate estimate would be 1, 2, 3, 5, 8,13,21,34,55…
However, this modified Fibonacci sequence in Agile estimation world is 1,2,3,5,8,13,20,40…
Each estimation is modified just for the sake of easiness of use of 20,40,80 and 100.
As you understand from the above sequence of Fibonacci numbers, it is clear that 2 is 2 times bigger than 1. However, the gap between 3 to 5 or even between 5 to 8 is not double. These nonlinear sequences work well in the high-level estimates as they reflect great amount of uncertainty. This will prevent one user story being too close to another.
The user stories that would be worked out in upcoming PI planning, would better to be estimated within one order of magnitude.
Enjoy using the planning poker with the above-mentioned Fibonacci series and get better high-level and accurate story estimates. This estimation method will improve project management.
What is planning poker?
Planning poker is a method to estimate story points and was developed and named by James Grenning. However, it became more well-known when Mike Cohn raised awareness of it in his book Agile Estimating and Planning.
Agile estimating and planning poker sessions
How does this and theories of planning poker cards relate to Agile Training? The estimation process for instance can be used as part of the planning technique when seen fit. Sprint planning is often an example of this where the solution is ironed out during the progress and changes from initial estimates, but the basic path is largely accounted for initially. Whether scrum poker, even traditional poker with a deck of playing cards, or another estimation technique, the same baseline principle is behind each iteration. It can help to account for the estimated effort or amount of work for example.
How does planning poker work?
At an agile estimation and planning meeting, all scrum team members will be given a deck of cards. A moderator will chair the meeting, but won’t participate in the estimation process.
The product owner will summarise a user story. Then the team will make their estimate by selecting the relevant card and placing it face down. Everyone then turns over their cards to show their estimations of the amount of work required. This with high or low estimates can justify and explain their choice.
The team continue to play planning poker until a consensus on the amount of work required is reached.
NB: this doesn’t have to relate to time. The units estimated could be story points, t-shirt sizes or another factor requiring a sequence of numbers.
When to use planning poker
Whilst this estimation method can take time, it does ensure that the scrum team members have their say and feel invested in the user story. It is an effective method of tackling a product backlog and determining the time required to resolve each backlog item.
It is an effective method to determine accurate estimates of development time required in software engineering for example.
Agile estimating and planning poker sessions
How does this and theories of planning poker cards relate to Agile Training? The Estimation process for instance can be used as part of the planning technique when seen fit. Sprint planning is often an example of this where the solution is ironed out during the progress and changes from initial estimates, but the basic path is largely accounted for initially. Whether scrum poker, even traditional poker with a deck of playing cards or another estimation technique, the same baseline principle is behind each iteration.
From product owners and shareholders to consultants and execs, software development teams, advertising teams and more, learn how your team members can become more agile teams and Schedule a Consultation with us today. Leadership Tribe specialize in agile development and training courses for your entire team to help you streamline the planning process and estimated effort and make it a more functional team today.