The 5 why method

1. State the Problem: Begin with a clear and specific problem statement. This is the symptom you've observed.

2. Ask the First "Why?": Ask why the problem occurred. Write down the answer.

3. Ask "Why?" Again: Using the answer from step 2, ask "Why?" again.

4. Repeat: Continue this process, each time asking "Why?" in response to the previous answer.

5. Identify the Root Cause: You'll know you've reached the root cause when asking "Why?" no longer yields a useful response. This is typically a broken process or a human-level action that needs to be changed.

A Classic Example: The Jefferson Memorial

Here's a famous, real-world example of the 5 Whys in action.

• Problem: The stone on the Jefferson Memorial in Washington, D.C. was deteriorating faster than on other monuments.

• 1. Why is the stone deteriorating?

  • Because it is washed frequently and harshly with chemicals.

• 2. Why is it washed so frequently?

  • To clean off the large amount of bird droppings.

• 3. Why are there so many birds?

  • Because they are attracted to the large population of spiders, which are a food source.

• 4. Why are there so many spiders?

  • Because they are attracted to the vast number of insects that swarm the memorial at dusk.

• 5. Why are there so many insects?

  • Because the lights are turned on at dusk, earlier than at other monuments, which attracts them.

Root Cause & Solution: The root cause wasn't the washing method, but the lighting schedule. By simply turning the lights on later in the evening, they solved the insect, spider, bird, and deterioration problems all at once, saving money and preserving the monument.