process
By repeatedly asking the question “Why” (five is a good rule of thumb), practitioners can peel away the layers of symptoms which can lead to the root cause of a problem. Often, the root cause is not evident at the surface level and it takes digging to get to it. The following process can be used to determine the root cause of a situation:
- Write down the problem statement.
- Ask "Why" the problem happens and write the answer down below the problem.
- Continue to exhaust possible causes for the problem until the team reaches consensus that the root cause has been identified.
Advantages
- Help identify the root cause of a problem
- Simple to use, does not require statistical analysis
- Identifies explicit processes
Disadvantages
- Assumes there is only one root cause for each problem
- Not repeatable
- Based on deduction, not observation
Example
Problem Statement: Customers are unhappy because they are being shipped products that don’t meet their specifications.
1. Why are customers being shipped bad products?
- Because manufacturing built the products to a specification that is different from what the customer and the sales person agreed to.
2. Why did manufacturing build the products to a different specification than that of sales?
- Because the sales person expedites work on the shop floor by calling the head of manufacturing directly to begin work. An error happened when the specifications were being communicated or written down.
3. Why does the sales person call the head of manufacturing directly to start work instead of following the procedure established in the company?
- Because the “start work” form requires the sales director’s approval before work can begin and slows the manufacturing process (or stops it when the director is out of the office).
4. Why does the form contain an approval for the sales director?
- Because the sales director needs to be continually updated on sales for discussions with the CEO.
In this case only four Whys were required to find out that a non-value added signature authority is helping to cause a process breakdown.
1. Why are customers being shipped bad products?
- Because manufacturing built the products to a specification that is different from what the customer and the sales person agreed to.
2. Why did manufacturing build the products to a different specification than that of sales?
- Because the sales person expedites work on the shop floor by calling the head of manufacturing directly to begin work. An error happened when the specifications were being communicated or written down.
3. Why does the sales person call the head of manufacturing directly to start work instead of following the procedure established in the company?
- Because the “start work” form requires the sales director’s approval before work can begin and slows the manufacturing process (or stops it when the director is out of the office).
4. Why does the form contain an approval for the sales director?
- Because the sales director needs to be continually updated on sales for discussions with the CEO.
In this case only four Whys were required to find out that a non-value added signature authority is helping to cause a process breakdown.