How many times do you get a question from a student like this?

What could I possibly use this math for?

Like a lot of things you use tools and skills in your life which you have learned and understand. The better you understand them the more likely you are to find some interesting, creative and useful uses of them.

Fibonacci numbers are very important topic in number theory and you see a lot of references and uses in art and nature. For this post I wanted to share a use I ran across while taking a training session in Agile projects.

This link has a very good explanation of use of Fibonacci numbers in Agile Planning. Below is an excerpt from the article:

Let’s start with a refresher for Fibonacci numbers. By definition, the first two numbers in the Fibonacci sequence are 0 and 1 (alternatively, 1 and 1), and each subsequent number is the sum of the previous two. Thus a Fibonacci sequence looks like: 0,1,1,2,3,5,8,13,21,34,55,89,144…

Most of the Agile Teams that I have come across estimate their work in Tee Shirt Sizes (especially at Feature or Epic level) and do a relative sizing in Fibonacci Numbers at the User Story level. But have you ever wondered why Fibonacci numbers? Why not just plain 1,2,3,4… numbers? Well, there is a reason for that.

The reason for using the Fibonacci sequence is to reflect the inherent uncertainty in estimating larger items. What this means is the larger the size of the card, the more uncertainty exist around what needs to be done to call the card “done-done”. Some people have noted that the Fibonacci sequence grows about the same rate at which we humans can perceive meaningful changes in magnitude, which could be another reason. By principle the larger stories can be sliced into smaller ones if possible. But it is not always possible to slice the work to provide business values. So, in keeping a user story larger, we introduce chances for uncertainty. It’s not possible to accurately estimate work that take days versus hours without introducing uncertainty. So by doing a Fibonacci sequencing for numbers, we account for such uncertainties.

Here is a example of using Fibonacci numbers for relative sizing of project work:

Agile - Fibonacci relative sizing

Agile – Fibonacci relative sizing