Visualizing 5 Whys

Pioneered in the modern age by Sakichi Toyoda, the 5-whys method is a way to dig into the true cause(s) of a problem in order to target its best corrective action to prevent recurrence.

Many problems appear to be simpler than to require 5 whys – for instance, “the forklift wasn’t charged overnight.” But simply reminding George always to plug in the forklift will only work until he forgets again. It doesn’t offer an improvement to the system. More “why” questions could reveal that George, who is the delivery driver, was pulled into a maintenance problem before he could park the forklift in its charging bay. Leaving late for deliveries, he assumed someone would park the forklift, but others assumed it was George’s job alone.

Using 5-why’s, we would discover: Why was the forklift left uncharged? The driver didn’t plug it in. Why didn’t someone else? They assumed it wasn’t their responsibility. Why? It was seen as a specific person’s duty, not as a daily company procedure. Why? The supervisor assigned duties rather than creating a team-oriented culture. Why? Top management hadn’t emphasized team culture with the supervisor. Charting it visually, allows you to see if each step truly flows from the prior answer, or if there’s another string to pursue.

If we stop after the first Why, we’d remind George. After Why 2, we’d lecture staff to “use their heads.” After Why 3, we’d make a sign to remind everyone to plug it in. After Why 4, we’d blame the Supervisor for not checking on the team. Determining our needed action after Why 5 reminds us that Management is responsible to develop, model and reinforce culture – so engaged team members would see and plug the forklift in before leaving for the day.

Even for ‘simple’ problems, more “Why” questions can reveal much about our system’s strengths and weaknesses. Using a visual diagram can help quickly grasp the relationships between elements, and other contributing factors.

Final thoughts: You know you have a true root cause when you can read the Why flow in reverse and see how each step was a result of the cause. And if acting on this cause didn’t prevent recurrence, seek other threads to pursue.