Whenever you are asked to specify the best tool for an application, you must first consider a few things before settling on an answer. You have to consider who is going to use it, what this tool would be used for (its application), and what the outcome is intended to accomplish. We know the answer to the first consideration to be operators. With this in mind, let us step through the remaining areas of concern to arrive at an answer.

1) What will the tool be used for?
Operators in the manufacturing and process industry environment play key roles in the overall reliability of equipment. First, they should be the most familiar with how their equipment should function under normal conditions. The difference between what that equipment should be doing and what it actually is able to do at a given moment in time is the definition of a problem.


Early indications of the onset of a problem can frequently be noticed by operators during the normal course of their duties if they are trained to be observant enough. While the use of predictive technologies such as vibration analysis, ultrasonics and infrared will give a much earlier indication, operators are sometimes called upon to be the last line of defense before failure occurs. So, one requirement of the tool could be that it needs to be able to encourage and facilitate the use of keen observation skills.

2) What end outcome is desired?
The quick answer to this question is that the chosen tool should be able to guide the operator through the root cause analysis (RCA) process down to the root cause(s) of the issue being examined. There are at least two other key outcomes that would be beneficial for this tool to accomplish as well. After the tool is used and the root cause(s) determined, there must be a system in place which allows for the resolution of the issue. The tool should also lend to easy application since the expectation would be that operators should be able to use it fairly regularly as a part of their daily regimen.

The Tool for the Job
With all this in mind, I would highly recommend a variation of the five-whys problem-solving methodology. The original five-whys technique was developed by Sakichi Toyoda and came to prominence in its use within the Toyota Production System. The architect of the Toyota Production System, Taiichi Ohno, described the five-whys method as “the basis of Toyota’s scientific approach; ... by repeating ‘why’ five times, the nature of the problem as well as its solution becomes clear.” Later, this technique was also adopted into the Six Sigma methodology.

The variation that I propose is called the Should-Actual Five-Whys (S-A-5Whys). In this variation, before tracing a defect or problem to its root cause, initial focus is spent determining when, in fact, a problem is occurring or about to occur.

How to Complete the Should-Actual Five-Whys

  • From keen observation, determine if a problem is occurring by comparing what the asset or process should be doing under normal circumstances to how it is currently performing.
  • Write down the specific problem, as indicated by the difference between the “should” and “actual.”
  • Ask “why” the defect or problem is occurring, and write the answer down below the problem.
  • Keep asking “why” until the team is certain that a root cause has been isolated.

Operators in a reliability-focused culture should have a questioning attitude and be very observant. The inclusion of the S-A-5Whys tool in their skill set will benefit the organization by the early identification and resolution of problems, leading to increased asset reliability.

About the author:

Carl March has a wealth of experience in the areas of maintenance, reliability engineering, systems modeling and design. Carl holds an undergraduate degree in mechanical engineering and a graduate degree in automotive systems engineering. As a reliability subject matter expert at Life Cycle Engineering, his passion and focus is in the transfer of knowledge in RCM, TPM, root cause analysis and Reliability Excellence to clients worldwide seeking to achieve manufacturing distinction. Carl has attained a significant level of professional recognition as a Certified Reliability Engineer (CRE) by the American Society for Quality and as a Certified Maintenance and Reliability Professional (CMRP) by the Society of Maintenance and Reliability Professionals. You can reach Carl at cmarch@LCE.com.