Ishikawa diagram: root cause

FIGURE 6.7. ISHIKAWA DIAGRAM ROOT CAUSE ANALYSIS TEMPLATE... 

A method used to illustrate and pinpoint the likely causes of a concern. It is sometimes referred to as a Root Cause Analysis. It typically uses an Ishikawa (wish bone) or tree diagram (see Figure C.2), where the main concern is depicted at the head of the fish spine and the most likely causes are shown as the attached bones. When identified the root cause can be modified to eliminate or reduce the concern. See also Root Cause Analysis (RCA). 

It is essential to diseover what the root cause of a problem is and after a team effort brainstorming session, it is helpful to construct a Pareto Chart, where groups of similar data are arranged in order of magnitude (Figure 18.14). This helps to eoncentrate on major problems. The so ealled 80/20 rule suggests that 80% of the problems result from 20% of the eauses. A eause and effects analysis is determined and a Fishbone (Ishikawa) diagram... 

From a standardized template, an Ishikawa diagram (Figure 6.7) was constructed during the root cause analysis. The template was displayed during the root cause analysis as a visual aid for the participants. The exact labels for the categories were somewhat flexible and were refined overtime. Participants identified as many contributing factors as possible, and the session facilitator added them to the chart as they were identified. 

There are many problem solving and improvement tools and techniques. The most common are root cause or cause and effect diagrams (also known as fish-bone or Ishikawa diagrams). Other techniques include flow charts, input-output analysis, scatter diagrams and why-why analysis. 

Ishikawa diagrams (Fishbone Charts)— used to create problem and solution visibility by grouping problem causes into branches. Often this is referred to as a cause-and-effect diagram. Using this tool in conjunction with the PDCA process helps to narrow down the root cause. 

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