Exploring Fishbone Diagrams: A Visual Tool for Root Cause Analysis

During their recent episode, Taylor, Carlisle, and Matt Sweeney discussed Exploring Fishbone Diagrams: A Visual Tool for Root Cause Analysis, here’s an excerpt from the episode:

Tobias: It’s the top of the hour, which means that it’s time for Jake Taylor’s veggies. Mark it down, 11:03 on the 33 minutes.

Jake: Okay.

Tobias: Timestamp.

Jake: Timestamp.

Matthew: I have to say quickly. I don’t think I ever realized that this was top of the hour. I thought you just jammed it.

Tobias: Ah, we just stick around.

Jake: Yeah.

Matthew: Oh, okay. All right.

Jake: It’s a rough approximation. All right. So, we are sliding in today with some amazing facts about fish. [chuckles] So, mark your calendars. So, this is surprising to me, but fish have been around for more than 530 million years. So, pretty successful as a biological entity. There’s around 32,000 species of fish in the world, more than all mammals, amphibians, birds and reptiles combined. Catfish have over 27,000 taste buds, while us humans only have 9,000. Now, thankfully, it probably for the catfish that they don’t eat each other, because catfish tastes terrible.

[laughter]

That’s just science. There’s this little fish called the cleaner wrasse. They’ve been shown to, not only respond to their own reflection in a mirror, but they attempt to remove marks on their own bodies when looking in a mirror. So, it’s a sign that they’re actually self-aware. Fish use tools, there’s an orange-dotted tuskfish, which has been filmed repeatedly smashing mollusks on rocks to get to the clams inside.

There’s this one fish called the goby fish that its survival depends upon being able to leap from one tide pool to another at low tide and without getting stuck on the rocks, which would be fatal for them. They have this very clever solution. While they’re swimming along at high tide, they’re actually memorizing the topography of the bottom of the ocean, and they make a mental map. So, when the tide goes out, they know where all the pools are and they know where to jump. The studies have shown that these little fish can remember this information up to 40 days later, which I find to be quite shocking. So, fish are quite a bit more impressive and interesting than I think I gave them credit for.

But what I really want to talk about today is these things called a fishbone diagram. I don’t know if you guys are familiar with this concept. I hadn’t really heard about it before, but I read about it in Luca Dellanna’s new book called Winning Long-Term Games. We’re having Luca on the show here when we come back from break. I’m excited to have him on. But in there, he talks about it’s this visualization tool that it’s used to systematically identify and present all the possible causes of a problem. So, they’re also known as Ishikawa diagrams, after its development by Dr. Kaoru Ishikawa, I believe it’s said in the 1960s.

Ishikawa was a key figure in quality management processes. Think about the Toyota lean manufacturing stuff that was happening in Japan. He was influenced by a series of lectures by Deming, who was one of the figureheads of that. Deming gave to Japanese engineers and scientists in 1950 and Ishikawa happened to be a part of that. So, these diagrams really help teams brainstorm and categorize potential causes of problems in a very structured way. It’s really getting at root causes instead of just symptoms, and they really turn complex problems into these much clearer visualizations.They’re part of the six-sigma lean manufacturing continuous improvement like Kaizen processes.

So, why is it called a fishbone diagram? They look like fish skeletons when they’re drawn. So, you take the defect or the problem that’s to be solved, and it’s shown as the fish’s head, and it’s typically on the far right of the diagram and then the causes extend to the left as fish bones. And so, these ribs branch of the backbone as the major causes of a problem, and then you could have little sub branches coming off of each main rib, and really as many levels as you want to require. So, they can be used in conjunction with that five whys exercise where you just keep asking why until you get at the root cause of an issue.

There are this different kind of catchy collections of different fishbone diagrams that can be done depending on the industry. So, I’ll give you some of them. In manufacturing, they have the five Ms, which are manpower and mind power, so physical and knowledge work, machine equipment, technology, materials, so your raw materials, consumables and methods. So, that’s the process that are being used. And then measurement and medium, which is like the inspection and the environment. If you’re trying to diagnose a problem in a manufacturing context, these five Ms drawn out on this fishbone diagram can help you to understand like, where might we be going wrong and get at the root cause of it.

There’s an eight Ps for product marketing, see a product, price, place promotion, people, process, physical evidence, and performance. And then the last one is in the service industry, there’s the five Ss, which are surrounding, suppliers, system skill and safety. So, those are just generic ones that people have built that they apply more generally. But I think this is a useful tool if next time that you have a problem that you’re trying to really figure out how to solve it.

Drawing one of these fish diagrams can really help you to unpack, especially in a team dynamic where everyone is trying to understand like where the problem is and what’s the root cause of it. And hopefully, this ties together a little bit with some fun facts with fish.

Tobias: Good one, JT.

Matthew: I like it. I’m still trying to figure out with catfish have 27,000 taste buds, why they basically eat garbage.

Tobias: I was going to say eat mud. [laughs]

Jake: Yeah, I got stuck on that too. I didn’t make it much past that. [laughs]

Matthew: It’s fun. I know exactly what you mean. I’ve seen in like, I don’t know if it’s an artist or a sculptor or something like that, but if you’re a fisherman as a taxidermy, you can get the actual fish skeleton and you could really see all the bones. I know exactly what you mean in terms of why they call it. That actually is an interesting way to frame it.

Jake: Yeah. If you just do a quick google search on the image of a fishbone diagram or Ishikawa diagram, you’ll see it and it’ll just immediately make sense.

Matthew: Right.

Tobias: I did that while you’re telling the story.

Jake: Yeah. Did it make sense?

Tobias: It does make sense. Yeah.

Jake: [chuckles] The math checks out.

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