At this point, historians agree that the golden ratio, the “divine” spiral, and the Fibonacci sequence predated Leonardo F. by a few hundred or more years, but modern agile practitioners have decided to agree to use the sequence to do basic addition and subtraction to determine team effectiveness, or velocity. It’s a bad idea.
But points are the whole reason we became “agile” and velocity is obviously the only indicator of progress when building software.
— Everyone Ever
Basically it’s like this. The golden ratio makes this amazing spiral showing in the image. Each number in the Fibonacci sequence adds to the spiral in term of it’s area and PI (the number) and a series of other factors. Simply put, if you have 4 numbers from Fibonacci, as in the case of a typical sprint with three or four activities, you can’t simply summarize the effort of an individual using simple math in the form of addition, and you infinitely cannot add the effort of six or eight team members by summing up golden numbers. Maybe their area, square, or some variation of square and PI (the number)?
The Fibonacci sequence has a purpose, and it’s to show the growth of something over time. In the case of agile, it’s the growth of the team’s capacity over the cycle of a sprint. You may need to consider several other factors such as the number of people on the team, their skill levels, the type of activities they are performing, and even their individual strengths and weaknesses.
In conclusion, the Fibonacci sequence and the golden ratio can be helpful in understanding the dynamics of a team, but it’s important to remember that they should not be used as a method of measurement for the effectiveness of a team or its members. There are more accurate methods available and it’s important to use those to ensure accurate results.
The Fibonacci sequence, or the golden ratio, are mathematical concepts present in nature, art and architecture. For example, the nautilus shell or the pattern of a sunflower’s seeds are both examples of the Fibonacci sequence. The golden ratio is often utilized in architecture, as its ratio of 1:1.618 is considered aesthetically pleasing. It has been used in the works of renowned architects such as Le Corbusier, and in the design of the Parthenon. Therefore, it is no surprise that the Fibonacci sequence and the golden ratio have become popular amongst agile practitioners in recent years.
“I wrote an article about the dangers of artificial intelligence and now my AI therapist isn’t speaking to me.”
— That’s a Rich Williams joke
However, many agile practitioners have resorted to using the Fibonacci sequence as a method of measuring team effectiveness. As the Fibonacci sequence is a series of numbers that increase incrementally, it is not an accurate way of measuring team velocity. The Fibonacci sequence is a mathematical concept and it is not an appropriate way to measure the effort of a team or its individual members. It is important to remember that the Fibonacci sequence is used to illustrate growth, rather than to calculate it.
In order to accurately measure the effectiveness of a team, it is important to consider several factors such as the number of people on the team, their skill levels, the type of activities they are performing, and even their individual strengths and weaknesses. Additionally, the Agile Manifesto states that “Working software is the primary measure of progress” and suggests delivering working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.
The concept of using the Fibonacci sequence for relative sizing in agile environments is misguided. It is important to prioritize a backlog and determine MVP, but this should not be done at the cost of compromising the principles of agile, such as prioritizing individuals and interactions, working software, customer collaboration, and responsiveness to change. Agile should not be reduced to a series of charts and graphs to compare velocity based on subjective story points.
Relative estimation can be a useful tool for having conversations and short-term predictability. However, it is not suitable for quantifying the work of a team, particularly when considering the different abilities, skills, and strengths of individual team members. The idea of using Fibonacci numbers for letting team members go is also flawed, as it does not take into account other factors such as their performance, experience, and impact on the project.
In an ideal scenario, the goal is to deliver a minimum viable product under budget and if possible, exceed expectations. This requires a hard estimate, contract, and agreement between the development team and the client.
Ultimately, the distinction between software development and building construction is noteworthy, as mistakes in software development can be corrected through bug fixes and app updates, while mistakes in building construction are much harder to rectify.
The challenge of subjectively comparing effort among stories in Agile methodologies can be addressed through the use of various methods such as t-shirt sizes, whole numbers, a scale of 1-10, and even Fibonacci numbers. However, it is important to note that these methods should not be used for adding and subtracting. On the other hand, time can be quantified in terms of years, months, weeks, days, hours and minutes, though it is worth mentioning that time estimation in Agile teams has been known to be unreliable.
The sum of the fibonacci numbers, whether properly calculated using the area pi spiral OR just summarized using basic addition, should be taken with a big coarse grain of sea salt flavored popcorn.
— Rich Williams (Me)
The purpose of using a metric such as velocity, which ultimately seeks to convert points to hours or dollars, is to support accounting needs. However, such calculations are limited by various factors such as holidays, interest, opportunity cost, and so on. Although the originators of velocity in Agile methodology were not mathematicians, there are mathematicians who are conducting research in the areas of time and money, with publicly available findings.
The use of numbers as a means of representation can be problematic as they are subject to manipulation by accountants, executives, and AI algorithms, which analyze the data and search for patterns through complex mathematical models. Using numerical values to quantify effort should only be done as a last resort, and it is always advisable to budget resources such as time and money.
I am proposing a revised use of T-shirt sizing to more accurately describe and label effort required to complete user stories in the form of what I call “SMLXD” or small, medium, large, extra-large, and double-XL. Individual contribution to a sprint could be described as SSLL or MLX and or shorthanded as a team with 3S.4M.2L.2X.D, etc. It’s honestly just a proposal, but something I’m looking forward to developing. How do you do math with SMLXD? You don’t. Instead you use it for what relative sizing was intended for: estimating complexity, uncertainty, and effort.*
Overall, the Fibonacci sequence and the golden ratio are wonderful mathematical concepts that have been present in the world for centuries. However, it is important to remember that they are not suitable for measuring team effectiveness or velocity. Instead, it is important to consider a range of factors and to follow the Agile Manifesto’s guidelines to accurately measure and track team performance.
Specifically, “Working software is the primary measure of progress,” and, “Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.” — The Agile Manifesto
Working software is the primary measure of progress
— The Agile Manifesto
PS: Never mind that the actual sequence has two “one’s” (1’s) so next time you’re playing planning poker, and someone says, “Which one?” You can say, “I know, right?” Because there’s two.
Rich Williams is an agilist in Dallas, Texas. He doesn’t know much, but he knows flawed logic when he sees it and calls it FLAWGIC to annoy his family and friends. He is a failed stand up comedian and once played bass in a popular hip hop outfit. He’s big, bald, and has a beard.
*scrum.org/resources/blog/practical-fibonacci-beginners-guide-relative-sizing
Rich Williams 