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Lean Manufacturing Tools by Nick Cray
September 6, 2022
Score Madison

Some Lean Manufacturing tools are too good to waste on just Manufacturers.

One of the early-developed lean tools, developed in the 1930s, is The 5 Whys. It is a problem-solving technique developed by the founder of Toyota Industries Corporation, Sakichi Toyoda. It's also useful for solving your business problems, regardless of your industry.

The 5 Whys is an iterative interrogative technique used to explore the cause-and-effect relationships underlying a problem (e.g. the root cause of a safety incident). The goal is to determine the root cause of a problem by repeating the question “Why?”. Each answer forms the basis of the next question.

Here’s a sample application:

Step #1: Have a clearly defined Problem Statement.

Step #2: Ask and answer why 5 times.

Example of a clearly defined problem statement: There is a significant decline in the revenue of our company.

  1. Why? Most of our stores experience stock loss.

  2. Why? Data from inventory reports are overlooked.

  3. Why? The turnaround of reports is slow.

  4. Why? It is tedious to complete paperwork.

  5. Why? Inventory audits using pen and paper are inefficient.

Step 3: Identify the ROOT CAUSE (ideally, it's the answer to the final WHY) and develop solutions or plans and countermeasures to mitigate it.

(from above) ROOT CAUSE: Inventory audits using pen and paper are inefficient.

Step 4: Develop and implement solutions to mitigate the root cause.

Sample solution: Use a digital inspection app to streamline inventory audits and reporting.

In Summary:

The 5 Why method is remarkably simple: when a problem occurs, you drill down to its root cause by asking "Why?" five times. Then, when a countermeasure becomes apparent, you follow it through to prevent the issue from recurring.

1. Teams often struggle to determine the root cause because they fail to agree on the problem statement. Team leaders should gather their teams and assist in establishing the problem based on current knowledge. It is crucial for 5 whys participants to refrain from blaming people and jumping to conclusions.

2. Know when to stop. The 5 Whys participants should pay attention to the logic of the cause-and-effect relationship. Otherwise, they might keep on coming back to the problem or conclude before they arrive at the root cause. Team leaders should train their teams on how to distinguish causes from symptoms. As a rule of thumb, teams should not go further when responses become illogical.

Good luck!

Written by Nick Cray, MS, MBA, Certified Score Mentor

PO Box 248
Madison, WI 53715
(608) 535-4978

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Funded, in part, through a Cooperative Agreement with the U.S. Small Business Administration. All opinions, and/or recommendations expressed herein are those of the author(s) and do not necessarily reflect the views of the SBA.

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