Fishbone diagram template
A fishbone diagram is a cause-and-effect chart. The problem sits at the head, a spine runs into it, and the possible causes hang off a set of bones, each labelled with a category such as methods, machines, people or materials. This free Word template gives you the diagram as a grid you can type straight into, ready-made bone sets for factories and for service businesses, and a page for testing which causes are real.
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It's also called an Ishikawa diagram, after the Japanese quality expert Kaoru Ishikawa. Reach for it when a problem could have many causes and you want the whole team's knowledge on one page before anyone settles on an answer.
What's in the template
A worked example from a fictional food manufacturer, using the six classic manufacturing bones; the causes in green were confirmed by data. The Word template sets the same bones out as a grid:
Fishbone diagram
| Problem (the head) | What, where, when and how much |
|---|---|
| Team and facilitator | |
| Date | |
| Bones used | The 6Ms, the service set, the safety set or your own |
1. The diagram
Top three bones, then the head, then the bottom three. Rename any bone to suit the problem, and add a sub-cause after a dash.
| Bone 1: Machine | Bone 2: Method | Bone 3: Material |
|---|---|---|
| The spine runs into the head: write the problem here |
|---|
| Bone 4: People | Bone 5: Measurement | Bone 6: Environment |
|---|---|---|
2. Bone sets to choose from
| Setting | Bones |
|---|---|
| Manufacturing (the 6Ms) | Machine, Method, Material, Manpower (people), Measurement, Mother Nature (environment) |
| Service and office work | Process, People, Systems and data, Policies, Suppliers, Customers |
| Health and safety incident | Place, Plant, People, Process |
3. Test the likeliest causes
| Cause | Bone | How we'll test it | Result | Confirmed? |
|---|---|---|---|---|
4. Actions
| Confirmed cause | Action | Owner | Due |
|---|---|---|---|
5. Parked for later
- Causes to look at another time
- Data still to collect
- Who else should see this diagram
How to run a fishbone session
- Agree the problem statement first: what, where, when and how much, with data if you have it, such as "jars on line 2 under the declared weight, 3% of output in week 32". Write it in the head.
- Pick four to six bones that fit the problem. Start from one of the sets below and rename freely. A bone nobody can fill usually means the category is wrong.
- Invite four to eight people who know the work, with a facilitator who isn't defending the process. Allow an hour.
- Brainstorm in silence first. Ten minutes with sticky notes, then place them on the bones together. It stops the loudest person setting the agenda.
- Ask "why does that happen?" of each cause and add the answers as smaller bones off it. Two or three levels is usually enough.
- Hold back judgement and leave names off while the diagram grows.
- Choose the likeliest causes and test them before acting. NHS England's guide suggests check sheets, interviews and process mapping at this stage.
Which bones to use
The categories are prompts, not rules. Three sets to start from:
| Setting | Bones | Good for |
|---|---|---|
| Manufacturing: the 6Ms | Machine, Method, Material, Manpower (people), Measurement, Mother Nature (environment) | Defects, scrap, breakdowns, low yield |
| Service and office work | Process, People, Systems and data, Policies, Suppliers, Customers | Delays, errors, complaints, rework |
| Health and safety incident | Place, Plant, People, Process | Accidents and near misses |
The safety set comes from HSE's investigation workbook (HSG245), which sorts the possible immediate causes of an accident or near miss under those four headings. NHS England's fishbone guide gives equipment, environment, procedures and people as examples and stresses choosing categories that fit the problem. In an office, swap Machine for Systems and data.
A fictional 40-person property management firm asking why tenants' deposits were returned late, for example, put "inspection booked only after the keys come back" on Process and "deposit account login held by one person" on Systems and data.
Example: under-filled jars at a fictional food manufacturer
The diagram above comes from a fictional 85-person sauce maker. Problem: in week 32, 3% of jars on line 2 were under the declared weight, against a usual 0.5%.
| Cause tested | Bone | How it was tested | Result |
|---|---|---|---|
| Worn filler nozzle | Machine | Measured against the maker's tolerance | Within tolerance: ruled out |
| New night-shift staff | People | Under-fill rate compared by shift | Same on every shift: ruled out |
| Cold sauce at start-up | Environment | Sauce temperature and fill weight logged every 15 minutes for a week | Under-fills cluster in the first two hours: confirmed |
| Limit set for old jar | Measurement | Checkweigher settings compared with the new jar's weight | Still set for the lighter old jar, so light fills passed: confirmed |
Actions: bring the sauce to filling temperature before the line starts; add "update the checkweigher" to the procedure for changing a jar or recipe; check it with test weights at every start-up. Under-fills were back to normal within two weeks.
Common mistakes
- A vague head, such as "quality problems", which no cause can be tested against.
- Forcing the 6Ms onto office work, which leaves empty bones and misses system and policy causes.
- Treating the diagram as the answer. Every cause on it is a hypothesis until data backs it up.
- One voice filling the bones, often the most senior person in the room.
- Stopping at the first layer. "Training" or "equipment" on its own isn't a cause anyone can act on.
- Names on the bones. Write the condition ("no handover between shifts"), not the person.
Frequently asked questions
What are the 6Ms in a fishbone diagram?
Machine, method, material, manpower, measurement and mother nature: the equipment, the way the work is done, the inputs, the people, how results are measured, and the surroundings. Plainer names such as people and environment work just as well.
How many bones should a fishbone diagram have?
Usually four to six. Fewer, and it stops prompting new ideas; more, and the causes start to overlap. NHS England's guide suggests four or more, chosen to suit the problem.
What's the difference between a fishbone diagram and the 5 whys?
A fishbone goes wide, collecting every possible cause; the 5 whys goes deep on one cause at a time. Use the fishbone first, then a 5 whys on the causes the evidence supports, and record the outcome in a root cause analysis.
Can I make a fishbone diagram in Word?
Yes. Angled bones are fiddly in Word, so this template uses a grid: top bones, head, bottom bones. In a live session, draw it on a whiteboard and type it up afterwards.