|The food truck can teach us about theory of constraints|
I have been reading a book entitled, “The Goal: A Process of Ongoing Improvement,” by Eliyahu M. Goldratt. It puts the reader in the shoes of a plant manager of a failing company. His wife is unhappy with all the responsibilities he has which keep him away from his family. His boss threatens to shut down his plant in 90 days. He is also dealing with his children and his aging parents. It is a trifecta of stress which would grind down any person.
The main character has to juggle these competing demands on his time and energy while confronted with the collapse of his marriage and loss of his job. He decides to concentrate on saving his job to provide for his wife and family. Over the course of the book, the protagonist learns about the theory of constraints and how to use it to save his plant. I will let you find out for yourselves if his marriage survives.
I am personally surprised that I did not get exposed to this idea sooner in my career. In layman’s terms, the theory of constraints posits that a system can only operate at the speed of its slowest sub-unit. For instance, if you have a food truck, you have someone taking orders, someone doing food preparation, and someone plating finished products and delivering them to customers. I realize that this example features a crowded food truck but stay with me. The cashier can take an order every two minutes. The owner can prep food for about 10 minutes per items on the menu. Plating and delivering food takes five minutes.
In this simple example, it is clear the slowest part of the process is preparing the food. If there are ten items on the menu, it takes 100 minutes or almost two hours. If done in a just in time fashion, then it takes 10 minutes. So, a busy developer visiting the food truck outside of the office has to wait almost 20 minutes to get a meal. This kind of service would put the food truck out of business. The bottleneck is food prep. Most food trucks avoid this issue by doing food prep in advance. It reduces meal time from 20 minutes to seven. It is a major improvement, and it might keep the food truck in business.
As a scrum master, it is important you recognize the bottlenecks which slow down the flow of value through the organization. Are product owners not writing stories? Are developers not doing test-driven development? Maybe the release process is taking too long. A good scrum master will figure this out and try to smooth worth through the system.
The theory of constraints contains plenty of mathematics and ways to measure flow through the system, but the general idea is to find the slowest part of the system and maximize it to find the slowest part of the system and maximize its output while preventing work from stacking up before the bottleneck and slack gathering behind it. Like many discoveries in science, engineering, and project management it is pretty simple once we understand it.
Until next time.