Design Thinking & Innovation

Fishbone Diagram

Sort possible causes of a problem into six categories so you can find the real source.

Time: 30 to 60 min
With: The team closest to the problem
You get: A structured list of possible causes and the few to investigate

How to use this worksheet

State the problem (the effect) as a specific, observable fact.
Brainstorm causes in each category. One cause per line, as specific as possible.
Ask "why" for each cause to find deeper causes and add them as their own lines.
Mark the three to five most likely root causes and plan how to verify them with data.

Problem (effect)

What exactly is going wrong? Include where, when and how much.

Prompts and example

Ask yourself

Can you measure it?
Is it a new problem or a persistent one?

Example

12 percent of orders shipped late in October, up from 4 percent in September.

Possible causes

Add causes under the category where they belong.

People

Skills, training, motivation, communication

Process

Methods, procedures, handovers

Equipment

Tools, systems, machines, software

Materials

Inputs, data, supplies, information

Environment

Location, conditions, culture, time pressure

Measurement

Metrics, monitoring, inspection, data quality

Prompts

Ask yourself

What changed just before the problem started?
Which causes can you verify with data this week?

Most likely root causes

Which causes will you investigate first, and how?

Prompts and example

Example

1) Stock counts in the system (verify with a cycle count this week). 2) Manual order check (measure the delay per order).

Causes per category

Before you finish

The problem statement is specific and measurable.
Each category was actually discussed, not skipped.
The shortlist has a way to verify each cause.

About the fishbone diagram

Kaoru Ishikawa introduced the cause-and-effect diagram in the 1960s for quality control. The categories shown here are the classic manufacturing "6Ms" adapted for general use.

The diagram structures brainstorming, it does not prove anything. Verify the shortlisted causes with data before acting.