The History and Spirit of Five Whys

An early automated loom designed by Sakichi Toyoda

In the late 1800s, a young carpenter realized that the future of human production would be driven by the evolution of machines. Being a practical person, this carpenter put himself to the task of creating automatic looms for textile production. It took him years to develop the automated “power loom” that would establish his legacy, but he was able to achieve his goal because he developed methodologies for understanding the then-new problems related to troubleshooting automated machines. One of those methodologies was the “root cause analysis” (now more commonly known as the “Five Whys” methodology), the goal of which is to see a problem as layers of cause and effect that can be peeled away to reveal the root cause, all simply by repeatedly asking… “Why?”

This careful, thoughtful approach towards problem-solving may be what allowed Sakichi Toyoda to build his power loom and propel his company, Toyoda Automatic Loom Works, to immense and global success. (Fun fact: Toyoda Automatic Loom Works, now better known as Toyota Motor Corporation, is actually still in the business of making textile looms)

The root cause analysis has since been described as “the basis of Toyota’s scientific approach” and its use has spread far beyond Toyota.

Why should software engineers care about the history of Five Whys? It teaches us two things:

1. Automated processes developed concurrently with methodologies for problem-solving automated processes. Even relatively simple wood and iron looms required thoughtful methodology. This strongly suggests that interconnected networks of complex, branched logic trees that operate on dynamic data (i.e. the services that comprise a web application) require us to apply methodologies with a similar level of thoughtfulness and rigor.
2. Root causes for the malfunction of a system are inherently always deeper than the (more-or-less) hairless ape that may or may not have twisted some dials and pressed some levers to trigger the incident. Five Whys allows us to dig deeper than the immediate incident or its organic catalyst and focus on the flaws within the system itself.

Evolution of the Five Whys

In the mid-20th century, Kaoru Ishikawa, an organizational theorist, took Five Whys further by employing a fishbone diagram (now known as an Ishikawa diagram) to approach the problem of Root Cause Analysis from a visual perspective. The strong visual cues of the diagram can be helpful in situations where there are many tangential issues that could distract from the root cause. Miro has a fishbone diagram template that you can use to get started.