The Fishbone Diagram has a number of categories to consider and might stimulate ideas about inputs missed during brainstorming. It is a tool that helps the team think of potential root causes to the problem from a number of different perspectives.

The tool encourages teams to look at multiple categories of inputs to discover the  root cause(s). It helps reach a common understanding of potential causes and exposes gaps in existing knowledge.

Description of problemSTEP 1: Draw a box on the far right-hand side of the paper with a horizontal arrow to the box and write the description of the problem in the box.

It is critical for the team to agree upon the problem under study. In most cases, the problem will be identical to the definition of Y.

Fishbone imageSTEP 2: As a team, come to consensus on the 4-5 major cause categories to use on the fishbone diagram. Write the names of the major cause categories above and below the horizontal line. Connect them to the “back bone” of the fish.

Typical cause categories include:

step 3STEP 3: Brainstorm a list of possible causes that could be driving the problem.

Brainstorming can be done by category or can be done prior to placing the potential causes on the major bones. It is recommended that the entire list of possible causes be generated first before attempting to place them on the major category bones. This keeps the creative flow of ideas.

Fishbone Diagram Step 4 and 5STEP 4: Place the brainstormed data causes in the appropriate cause category.

STEP 5: For each cause, drill down into “causes of the causes” by asking repeatedly, “why does this happen?” Arrange contributing causes on the smaller bones.