Ishikawa Fishbone Root Cause Analysis

This 45 minute guide uses Ishikawa fishbone root cause analysis to solve complex operational issues. Map contributing factors across structured categories to identify and fix root causes.

5 time blocks, 45 minutes in total.

Time blocks

Define Problem Statement: 5 min
Write a single concrete symptom at the far right of your workspace
Map Primary Categories: 5 min
Draw six main category branches leading to the central spine
Brainstorm Contributing Factors: 15 min
Add specific contributing causes along each category branch
Apply 5 Whys to Key Causes: 10 min
Ask why each primary factor occurred to reach underlying roots
Prioritize and Define Countermeasures: 10 min
Select the highest impact root causes and assign clear action steps

About this routine

Developed by Kaoru Ishikawa in the 1960s for quality management at Kawasaki Steel, an Ishikawa fishbone root cause analysis systematically organizes potential causes of a failure. Instead of jumping to quick conclusions, individuals and teams group potential factors under six standard domains: Methods, Machines, Materials, Manpower, Measurement, and Milieu.

The analysis begins by writing the outcome or flaw at the head of a main horizontal spine. Major diagonal bones branch off to represent the core operational domains. By brainstorming sub-causes along each branch and applying probing questions, you highlight hidden structural issues rather than temporary surface symptoms.

Running this 45 minute exercise ensures your problem solving stays methodical and objective. Following a structured timing blocks off rushed assumptions and forces thorough examination before taking corrective action.

Why this routine works

Identifies structural root causes instead of treating surface symptoms
Categorizes complex operational breakdown points across six standard domains
Prevents premature conclusions during team or solo troubleshooting

FAQ

What are the 6 Ms in an Ishikawa diagram?

The 6 Ms are Methods, Machines, Materials, Manpower, Measurement, and Mother Nature (Milieu). They serve as primary branch categories for organizing potential causes.

How long does an Ishikawa root cause analysis take?

A focused session takes 45 minutes using this five step structured layout.

Who created the fishbone diagram?

Kaoru Ishikawa developed the cause and effect diagram in the 1960s to improve industrial quality control.

Sources

Guide to Quality Control, Kaoru Ishikawa (Asian Productivity Organization)
Quality Improvement Tools: Cause and Effect Diagram, American Society for Quality (ASQ)