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Fishbone (Ishikawa) diagrams: 5 steps to find causes of complex business problems

Use these simple yet powerful tools to identify and analyze the root causes of challenges

5-minute read

Can a fishbone help you solve complex problems in your business? Kaoru Ishikawa thought so. Ishikawa was a legendary Japanese management guru who revolutionized quality management.

One of his inventions was the fishbone diagram, also known as an Ishikawa diagram. Operational efficiency experts worldwide use this simple yet powerful tool to find, visualize and analyze underlying causes of business challenges and develop solutions.

It’s called a fishbone diagram because possible causes of the problem are written on an image that looks like the bones of a fish. The head represents the problem, while each bone of the fish is a function or department of the business.

A fishbone diagram is a highly visual tool that can spark great conversations, helps you zero in on the root cause of problems across multiple functions and leads to many ‘aha’ moments for your team.

What is a fishbone diagram?

“A fishbone diagram is a highly visual tool that can spark great conversations, helps you zero in on the root cause of problems across multiple functions and leads to many ‘aha’ moments for your team,” says Manuel Gogolin, Co-Lead Impact, Growth and Productivity at BDC, who coaches companies on operational efficiency.

“A lot of organizations have their heads down focusing on day-to-day operations and just dealing with the symptoms of problems. A fishbone diagram provides an opportunity to step back, brainstorm around key challenges and drill down to the root causes so problems don’t keep resurfacing.”

5 steps to using the fishbone diagram for problem solving

Gogolin breaks down the problem-solving process using the fishbone diagram into five steps.

1) Involve your team

Engage your team in the exercise from the beginning.

  • Employee involvement helps build consensus around the nature of problem being addressed, underlying causes and solutions.
  • You get input from each function that may be responsible for causing the problem.
  • It’s consistent with the lean methodology. One of the three key tenets of lean is to involve the people closest to a problem who deal with it every day.

Gogolin says five to 10 people are typically involved in a fishbone exercise. This should include members of the leadership team and people from other functional areas of the business. While a facilitator with experience in operational efficiency can lead the process, this exercise can also be done whenever a problem surfaces.

Teams can meet in person and work with a fishbone diagram put up on a wall, using sticky notes. The exercise can also be effective in a virtual environment.

2) Describe the problem statement

Next, the team should get consensus on the issue to be discussed and articulate it in a clear, concise problem statement. This should be no more than a short sentence and is typically written on a sticky note that is put at the head of the fish.

Problems most commonly have to do with one of three areas:

  • costs
  • timeliness (e.g. lead time)
  • quality

Example problem statements might read:

  • our invoicing process is too slow
  • lead time is too long
  • we’re running out of room in our facility
  • customer satisfaction has declined
  • warranty claims are too high
  • our cash flow management is poor

3) Decide on the major factors

Now it’s time to define the “bones” of the fish. These are called the “major factors.” Each bone represents a function or department of the business. There’s no set list or number of major factors, though some common definitions do exist. With your team, pick a set of categories that are the most relevant for your problem or company. Some common examples:

  • 5 M’s: manpower (people), machines, material, method and measurement (process)
  • 8 M’s: same as 5 M’s plus mission (purpose), management (leadership) and maintenance
  • 7 P’s: properties, people, place, product, physical evidence, promotion and price
  • 4 S’s: surroundings, suppliers, systems and skills

Label each bone of the fish with a major factor.

Example of a 5M fishbone (Ishikawa) diagram

4) Identify possible causes

Going one major factor at a time, each participant uses a real or virtual sticky note to write down possible causes of the problem in that function. If invoicing is slow, causes in the manpower (people) bucket could include insufficient personnel, inadequate training and poor support from other departments.

Add a sticky note on the manpower bone for each cause, then work your way through the rest of the major factors. The facilitator should clarify any stick notes that are unclear and make sure they’re put on the right bone. Some bones may end up with more possible causes than other bones.

The facilitator can encourage further discussion by using the “five whys” method—asking “why” at least five times to find the root cause of a problem. For example, if a possible cause of slow invoicing is that you’re short-staffed, the process could look like this:

Q1: Why is invoicing slow?

A: We’re short-staffed.

Q2: Why are we short-staffed?

A: Sales have increased, and we don’t have enough people in billing to keep up.

Q3: Why don’t we have enough people?

A: Turnover is high.

And so on at least five times altogether. For simpler problems, the five-whys technique can also be used in place of a complete fishbone analysis. The latter is better suited to more complex problems or those involving multiple functions in the business.

5) Choose the top causes

Now go through the bones one by one and discuss the causes. Consolidate causes that are similar and talk about relationships between causes to trace them back to underlying issues.

Then make a short list of the top five underlying causes. To do this, you can develop a consensus, or you can give every participant one or more votes and tally up the results. You can also use Pareto analysis to identify issues that have the biggest impact on your business. It’s helpful to summarize the results in a findings report.

With the top causes chosen, you can develop solutions to address the causes and an action plan for implementing initiatives.

“Avoid getting to solutions too quickly,” Gogolin says. “People sometimes have an automatic tendency to start thinking about solutions right away. It’s important to finish the root cause analysis first to identify and prioritize the causes of the issue so the solutions are effective.”

Want to get more information and advice to help solve your operational problems? Read our free guide to learn more about the basics of operational efficiency or fill out a form to start talking with one of our experts.

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