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Hello readers,

Today we are discussing Ishikawa diagrams, or in the spirit of the end of the Scottish salmon season later this month, Fishbone diagrams. Although I emphasise that no fish were harmed in the making of this blog.

Sometimes, when trying to work out the cause of a problem, we can’t see the wood for the trees. All too often, this is the case when trying to figure out the causes of a problem encountered in your work. After all, is so easy to focus on the symptoms, and not get to the root cause. Indeed, there is often not one single root cause, but several interrelated issues that wind their way through into a turbulent confluence that becomes the overall problem; whether it be poor customer satisfaction, difficulty completing projects on time or an example we have encountered such as the slightly more specific case of university applications becoming ‘stuck’ in the system!

Fear not however, for there is a concept that has been developed to solve this very problem, in the form of the Fish Bone Diagram. The Fish Bone diagram, (also known as an Ishikawa diagram, after its creator Kaoru Ishikawa) is a solution that does indeed draw inspiration from fish, but not from their passage down rivers and streams.

Best underpinned by an analytical framework such the 5s (Systems, Skills, Safety, Suppliers, Surroundings), or the 7ps (Promotion, Place, People, Process, Price, Physical Evidence and Products), the fishbone diagram is a fantastic tool that allows a team to brainstorm what the overarching causes of a problem are, and then drill down into the specific root cause/s, and this is how it works:

How to create an Ishikawa diagram:

  • Firstly, you need the head of the fish. What problem do you want to solve? Consider this carefully, as it will forms the basis of your diagram.Draw an arrow across the page pointing to your problem, creating the spine.
  • What are the core issues at the heart of your problem? It is helpful to start with a framework in order to underpin your analysis (like the 6 M’s of manufacturing, 7 P’s of marketing, of the 5 S’s of services), but it can also be a bespoke solution.
  • With your team, identify the problem you want to solve and write it down to the side of the paper. Draw an arrow pointing to it.
  • Categorise the causes and draw these on the diagram as ‘branches’ or ‘bones’ of the central spine. the diagram will look like a fish skeleton at this point.
  • Flowing from the main causes, drill down a level and identify specific contributory causes and note down on each corresponding branch.
  • Take a moment to reflect and decide on the major and root causes. These are the ones which you can start to solve. Keep asking WHY and you will eventually reach your root cause!

So, we have discussed the why and how, but what is the relevance of this concept for Lean more broadly? Lean largely centres on stamping out waste by fostering a culture of efficiency and continuous improvement (great previous blog of ours, if we may say so, here on the fundamentals of Lean). The Fishbone Diagram naturally fulfills the primary purpose of identifying the root cause of issues, but does so in the most direct way and cuts out time wastage on coming up with those root causes, one of the sources of loss if you like.

So there you have it! Feel free to retweet us your Fishbone Diagram and have a great week!

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