What is it, and why use it?
A fishbone, or Ishikawa diagram, groups possible causes of an observed effect into categories. The branches organize ideas without proving that an idea is true.
It helps a mixed team explore explanations beyond the most obvious person or department.
Explore the Fishbone / Ishikawa features and local-file workflowWhen to use it
Use it during early investigation when the team needs a broad, organized set of hypotheses.
When another tool fits better
Use Root Cause Analysis Builder for detailed validation or 5 Whys to investigate one branch more deeply. Use Pareto to prioritize measured categories.
Before you start
- A specific observable effect and its scope.
- People familiar with different parts of the process.
- Initial evidence and a willingness to keep hypotheses unvalidated.
Use fictional or approved non-sensitive information. Do not include patient details or proprietary records in practice worksheets.
Step-by-step in CI Tools
Enter the observable problem or effect and review the customizable 6M categories. Rename categories to fit your process.
Add possible causes and subcauses beneath appropriate categories. Keep distinct hypotheses separate.
Select a diagram label or list entry to record evidence and verification status.
Use Move to change a category or parent without losing the cause identity. Explore in 5 Whys creates an independent investigation with source context.
Prioritize evidence gathering, not the longest branch. Save the diagram and its investigation notes to a computer file.
A fishbone organizes possibilities, not conclusions
Attach observations to a specific hypothesis and retain verification status. Several branches may contribute at once. Avoid voting a hypothesis into fact solely because the team agrees it is plausible.
Completed worked examples
Demonstrations only: all organizations, observations, targets and results below are fictional. They are not clinical instructions or universal performance standards.
Healthcare operations — fictional
Incomplete room preparation
Starting information: A fictional unit brainstorms why preparation checks are missed.
| Method | Checklist sequence does not match actual preparation |
|---|---|
| Materials | Some supplies are stored away from the preparation area |
| Measurement | Missed checks are not defined consistently |
What the result means: These are hypotheses. Observe preparation and test the definitions before choosing a countermeasure.
General business — fictional
Packing-label mismatch
Starting information: A fictional warehouse investigates label errors.
| Equipment | Printer settings differ between stations |
|---|---|
| Method | Two label templates remain accessible |
| People / environment | Handover information and interruptions may influence selection |
What the result means: The category names help the discussion but do not establish causation. Investigate evidence across several branches.
Practise in a separate worksheet
Open the tool’s built-in synthetic sample as a new editable worksheet. It may differ from the worked demonstrations above. It never replaces an existing worksheet. Save any work you want to retain to your computer.
Open built-in practice worksheetYou’ll be asked to log in if needed. No worksheet is created just by reading this page.
Common mistakes and how to avoid them
- Using categories as a compulsory checklist: adapt them to the process.
- Treating more suggestions as stronger evidence: test important claims.
- Writing a proposed solution as a cause: describe the mechanism being investigated.
Interpret the result
A completed diagram is an investigation agenda. Identify which hypotheses matter, what evidence exists and what to check next. Use a focused investigation to test causal links rather than counting branch entries.
Record the assumptions and unanswered questions alongside the result. Use the relevant local review process before making operational decisions.
Credible further learning
These independent educational resources explain the methods. They do not endorse CI Tools Suite. Some external resources have their own access requirements.
- ASQ: Cause analysis tools (external resource)
- IHI: Quality Improvement Essentials Toolkit (external resource)
Resource links reviewed 29 October 2026. Our interface instructions and fictional examples are original CI Tools learning material.
Put the method into practice
Start a new worksheet, use the guide beside your work and keep an editable .citools copy on your computer.
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