The 5 whys?????
Invented by Toyota's founder and great inventor Sakichi Toyoda and integral part of Toyota's Kaisen philosophy, the 5 whys is a powerful tool.
The 5 why analysis is widely used across a wide array of industries as a tool to discover the root causes of a problem.
It is a common fact that people try to solve a problem by solving the issues that are obvious to them. While this provides a short-term solution, the real problem reappears from another angle sooner or later. Finding a long term solution involves defining the root of that problem.
Consider the example of a dying tree. To make it look better, the first apparent solution would be to cut dried, wilted leaves and sure, the tree will look fantastic! For a while... Until the other leaves start wilt and the tree perishes.
To find a real solution, we have to find out why the leaves are wilting. Perhaps a lack of water? Or some voracious insects? Or a malicious bacteria? The point is that once the root cause of the problem is identified, a solution can be found.
The 5 why analysis helps targeting the cause of a problem with precision.
The concept of 5-why is simple:
Fishbone Diagram:
Step 1: On a sheet of paper, set the "spine" of the fish. This is where you write down the effect you have identified. In our example, "the tree is dying"
The 5 why analysis is widely used across a wide array of industries as a tool to discover the root causes of a problem.
It is a common fact that people try to solve a problem by solving the issues that are obvious to them. While this provides a short-term solution, the real problem reappears from another angle sooner or later. Finding a long term solution involves defining the root of that problem.
Consider the example of a dying tree. To make it look better, the first apparent solution would be to cut dried, wilted leaves and sure, the tree will look fantastic! For a while... Until the other leaves start wilt and the tree perishes.
To find a real solution, we have to find out why the leaves are wilting. Perhaps a lack of water? Or some voracious insects? Or a malicious bacteria? The point is that once the root cause of the problem is identified, a solution can be found.
The 5 why analysis helps targeting the cause of a problem with precision.
The concept of 5-why is simple:
- Identify the problem.
- Ask why it happened? Try to come up with all imaginable causes.
- For each cause identified, ask again why it happened?
- Repeat until have identified the root cause (5 times is usually sufficient).
Fishbone Diagram:
Step 1: On a sheet of paper, set the "spine" of the fish. This is where you write down the effect you have identified. In our example, "the tree is dying"
Step 2: Choose a cause category: causes can almost always be found in one or more of those categories. Concentrating on those categories individually brings a more methodical approach.
- 3M’s and P – Methods, Materials, Machinery, and People
- 4P’s – Policies, Procedures, People and Plant
- 6M’s – Machine, Method, Materials, Measurement, Man and Mother Nature
- 8P’s – Price, Promotion, People, Processes, Place / Plant, Policies, Procedures & Product
- 4S’s – Surroundings, Suppliers, Systems, Skills
- Equipment, Process, People, Materials, Environment, and Management
- Step 3: The first why?
Step 4: The second why?
Step 5: The second why?
Step 6: The third why?
Step 7: The fourth why?
Step 8: the fifth why?
Step 9: add more reasons if required.
Step 9: Repeat for each of the cause categories. At the end your fish-bone diagram should look like this:
Image from mindtools.com