What is a fishbone (cause & effect) diagram?
A fishbone, or Ishikawa, diagram helps a team find the root cause of a problem instead of fixing the first symptom they notice. The problem sits at the head; the bones are categories of possible causes — people, process, equipment, materials, environment and measurement — with specific causes noted along each one.
When to use it
- Investigating a recurring problem such as late deliveries or failed builds.
- Running a blameless post-incident review.
- Quality and process improvement work, including Six Sigma projects.
How to make a fishbone (cause & effect) diagram in SketchFlow
- Step 1: Open the fishbone template in SketchFlow.
- Step 2: Write the problem in the red head box as a measurable effect, for example 'Late deliveries'.
- Step 3: Rename the six category boxes if different groupings fit your problem better.
- Step 4: Brainstorm causes and place each as a text note beside its category (T).
- Step 5: Circle the likely root causes, then export the diagram for your report.
Tips for a better result
- Ask 'why?' about each cause until you reach something you can act on.
- State the problem, not a solution, in the head.
- Back up suspected root causes with data before acting.
Questions about this template
What are the 6 Ms of a fishbone diagram?
A common set is Manpower (people), Methods (process), Machines (equipment), Materials, Mother nature (environment) and Measurement.
Why is it called a fishbone diagram?
The finished diagram looks like a fish skeleton: the problem is the head, the main line is the spine and the cause categories are the bones.
Who invented the fishbone diagram?
It is credited to Kaoru Ishikawa, who popularised it for quality management, which is why it is also called an Ishikawa diagram.