What is 'Ishikawa Diagram'

An Ishikawa diagram is a diagram that shows the causes of an event and is often used in manufacturing and product development to outline the different steps in a process, demonstrate where quality control issues might arise and determine which resources are required at specific times. The Ishikawa diagram was developed by Kaoru Ishikawa during the 1960s as a way of measuring quality control processes in the shipbuilding industry.

Also referred to as a "fish bone diagram" or "cause-and-effect diagram."

BREAKING DOWN 'Ishikawa Diagram'

Ishikawa diagrams are sometimes referred to as fish bone diagrams, herringbone diagrams, cause-and-effect diagrams or Fishikawa. They causal diagrams created by Kaoru Ishikawa to show the causes of a specific event. They resemble a fish skeleton, with the "ribs" representing the causes of an event and the final outcome appearing at the head of the skeleton. The purpose of the Ishikawa diagram is to allow management to determine which issues have to be addressed in order to gain or avoid a particular event.

Other common uses of the Ishikawa diagram include using it as a methodology for creating product designs that solve practical problems. It can also be used in quality defect prevention to identify potential factors causing an overall effect. Each cause or reason for imperfection is a source of variation. Causes are usually grouped into major categories to identify and classify these sources of variation.

Process to Make an Ishikawa Diagram

To make an Ishikawa Diagram, a group will need a white board, flip chart and some marking pens.

  1. The group should agree on a problem statement (effect).
  2. Write the problem statement at the center right of the flipchart or whiteboard, box it and draw a horizontal arrow running to it.
  3. Brainstorm the primary categories of causes for the problem. For instance, it might make sense to start with these generic headings: 
    • Methods
    • Machines (equipment)
    • People (manpower)
    • Materials
    • Measurement
    • Environment 
  4. Write the categories of causes as branches from the main arrow.
  5. Brainstorm possible causes. Ask: “Why does this happen?” As each idea is given, the facilitator writes it as a branch from the appropriate category. Causes can be written in several places, if they relate to several categories.
  6. Ask the question “why does this happen?” again. Write sub–causes branching off the causes. Continue to ask “Why?” and generate deeper levels of causes. Layers of branches indicate causal relationships.
  7. When the group runs out of ideas, focus attention to areas in the chart where ideas are thin.
  1. Decision Tree

    A decision tree os a schematic tree-shaped diagram used to determine ...
  2. Risk Analysis

    Risk analysis is the process of assessing the likelihood of an ...
  3. Bottom Fishing

    Bottom fishing is the process of investing in assets that have ...
  4. Shell Branch

    A shell branch is a branch location of a U.S. chartered bank ...
  5. Pilot Fishing

    Pilot fishing is a type of pre-marketing of an IPO that involves ...
  6. Branch Automation

    Branch automation is banking automation that connects the customer ...
Related Articles
  1. Investing

    Alphabet, Inc. Helps Crack Down On Illegal Fishing

    Google has partnered with non-profits to use a big data approach to solve the illegal fishing problem.
  2. Investing

    A Checklist for Assessing Your Investment Risk

    In order to make the best investment decisions, it's important to be aware of and understand how much risk you are willing to take.
  3. Trading

    Naked Call Writing: A High Risk Options Strategy

    Learn how this aggressive trading strategy is used to generate income as part of a diversified portfolio.
  4. Personal Finance

    Tapping Mind Maps for Better Financial Planning

    Here's how to use mind maps to better assist your financial planning.
  5. Investing

    Due Diligence in 10 Easy Steps

    Learn how due diligence offers key information for potential investments. Find out how these 10 important steps can give you a balanced views of pros and cons of your investments and allow you ...
  6. Investing

    Biotech Musical Chairs: Who Leads Next

    The biotech sector as measured by the iShares Nasdaq Biotech ETF is down another 1.40% today.
  7. Investing

    Buying a Home: What You Should Consider

    Whether you’re a novice or you’re experienced in the home buying market, here are some things to think about as you move forward in the process.
  1. Short Selling Vs. Put Options: How Payoffs Differ

    The payoff difference between the two comes down to the difference between option and obligation. Read Answer >>
  2. What is the best way to measure the total market?

    There is a variety of market indices which function as statistical gauges of the market's activities. Many investors look ... Read Answer >>
  3. Why do stock prices change based on news reports?

    Stock prices move up and down due to fluctuations in supply and demand. Learn how this relationship is tied into news reports ... Read Answer >>
Trading Center