Ishikawa diagram

Reviewed by Apex Insurance Brokers · Last reviewed 2026-06-22

Reviewed by Apex Insurance Brokers · Last reviewed 2026-06-22

Category: Risk identification & assessment · Reviewed by Jake Leat, Associate Director · Last reviewed

Ishikawa diagram is the formal name for the fishbone or cause-and-effect diagram, named after its developer Kaoru Ishikawa (1915–1989), the Japanese quality engineer who introduced it as part of his “seven basic tools of quality”.

Ishikawa’s seven basic tools

1. Cause-and-effect (Ishikawa / fishbone) diagram
2. Check sheet
3. Control chart
4. Histogram
5. Pareto chart
6. Scatter diagram
7. Stratification (or flow chart)

These tools were intended to be usable by anyone — including front-line operators — without specialist statistical training, and underpin much of modern total quality management.

Relevance to insurance

Ishikawa’s tools are widely used in operational risk and claims handling improvement programmes. They appear in continuous improvement (lean / six sigma) methodologies that insurers and intermediaries apply to claims fraud control, cycle-time reduction and complaint-handling.

References

• Ishikawa, K. (1985). What Is Total Quality Control? The Japanese Way. Prentice-Hall.
• ASQ. Quality tools.
• IEC 31010:2019.

Cross-references

• Fishbone diagram
• Root cause analysis

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