Process improvement project - Analyze -

Also known as Cause & Effect Diagram.

A useful way of grouping and presenting ideas from a brainstorm


What are the possible causes of this effect?

This is similar to Affinity Diagram, and uses post-its, but has a narrower more focused issue statement


STEP 1 -

Create your categories of Causes.  Examples are People, Equipment, Method, Materials and Environment

fish-bone diagram
Fish-bone Diagram
Fishbone Diagram
STEP 2 -

Using a shape similar to a fish skeleton, place your Issue statement in the head of the fish on the right side.  You can phrase it as a question e.g. “What are the causes of…”, or “Why does this occur?”

Fishbone Diagram
STEP 3 -

Depending on the number of categories listed in step 1, add the number of fish bones and insert the headings

Fishbone Diagram

STEP 4 - 

Place the brainstormed ideas (causes) under the categories

STEP 5 -

For each possible cause, ask the question “why does this happen?”  List the responses off from the brainstormed ideas in step 4 to create smaller bones

Fish-bone Diagram
STEP 6 - 

To help with the previous step, use the 5 Whys tool to help

STEP 7 -

Now the diagram is complete, look for possible causes that appear repeatedly, and to identify where you need to gather data as a measurement


STEP 8 -

As you measure the data for each cause, you can update the diagram to indicate if it is a True cause, or not.  A Scatter diagram is useful to complete this step.