Dig Deeper with 5 Whys

The 5 Whys is another Six Sigma tool used to effectively uncover any underlying causes to a problem. Unlike most Six Sigma tools, 5 Whys doesn’t need statistical data or hypothesis. This simple technique is used in Six Sigma’s Analyze phase in the DMAIC model and is very similar to a child’s series of “Whys”. The ultimate goal of which is to dig deep into the real cause of the problem.

This universal tool can be applied to almost any problem from the simplest everyday snags like getting to work every morning to highly sensitive issues in the corporate or manufacturing world. This methodology was developed by a Japanese industrialist and inventor, Sakichi Toyoda, who is also the founder of the Toyota Industries. The 5 Whys was first applied to the motor manufacturing of Toyota Motor Corporation.

Problem #1: Habitually late for work.

  • Why is the employee late? Because she woke up late.
  • Why did she wake up late? Because she slept late last night.
  • Why did she stay up too late? Because she watched a late night show on TV.
  • Why did she watch TV late in the night? Because she can’t sleep.
  • Why can’t she sleep? Because she has insomnia.
  • Why is she insomniac? Because she is worrying.
  • Why is she worried? Because she’s thinking that she might lose her job.
  • Why is she worried of losing her job? Because she’s not getting any feedback from her boss regarding her work.

As showed in the first example, you can go as many “Why’s” as you think necessary until you are contented that you already have the answer or the underlying reason behind the problem. Based on our first probing series, if we have stopped after the third why, we might come into the conclusion that watching TV is the cause why the employee is habitually late in coming in.

To solve the problem, we can ask her to stop watching late night TV shows. That will not solve the problem. The employee will still be awake even if she stopped watching. By knowing the real reason, we can correctly address it. In this case, simply talking to the employee, giving her the necessary feedback and performance evaluation and assuring her of employment will alleviate her condition, thus effectively solving the problem.

Problem #2: High level of rejects of pencils from Quality control.

  • Why are the pencils rejected? Misalignment of leads.
  • Why are the leads misaligned? Poor workmanship.
  • Why are the workers not performing well? The factory is too hot.
  • Why is the factory too hot? No proper ventilation is in place.
  • Why is there no proper ventilation in place? The recent expansion has crowded the factory, disrupting the present ventilation system.

Just like the first example, stopping after the second or third why will give you a different answer or cause to the problem. Engaging the 5 Whys also eliminate assumptions that are usually causes more problems than solve it.

One good indicator that you have arrived at the real cause is if the answer already provides the solution. You can also your answer the final one if it is to a process. Before we blame the people behind the failure, it is always good to look over the process. For the first example, the employee is agitated because she’s not getting any performance assessment, thus her problem on job stability.

Without the 5 Whys we could easily conclude or assume that the problem is on the employee’s unprofessional behavior. For the second case, blaming and firing the workers for poor workmanship will not really solve the problem. New workers will still have the same shortcomings until the root cause is resolved.

Steps to complete the 5 Whys

Identify the problem – This is usually not a part of the investigator’s job as problems will present itself. But it is upon the analyst to determine the scope and focus of the problem and the limitations of the research.

Prepare for the research – This step will include the formulation of the initial questions, who to ask, and a background study of the problem and on the factors that are relevant to it.

Research – This is the main part of the process. Here the investigator will ask the whys and collect actual answers. There will be several deviations to the pre-formulated questions as the next questions will depend upon the answer provided by the interviewee.

Analyze the research returns – The investigator can either form a team to discuss the results of his survey. As it will provide diverse answers and opinions from the respondents, it is the job of the analyst or investigator to come up with the majority or the strongest answers. The investigator or the team will also have to discard the information that they perceives as irrelevant, inconsequential or over-the-top responses.

Determine the root cause – This is the conclusion part wherein the team will narrow down to a specific cause of the problem

Recommend a solution – As the research will also provide a lot of information as the most feasible resolution to the problem, the investigator is in a high position to provide good recommendations.

The 5 Whys can be accomplished in a team effort very much like the Ishikawa process or as an individual work. One of the major limitations of this process is the fact that it relies solely upon human judgment. This is also the biggest criticism of 5 Whys. The whole process, from formulating the questions, research and to the process of elimination and evaluation is very subjective and depends on the opinion and ruling of the investigator or team of investigators. No verifiable data or facts are needed to complete the process.

Te process also depends a lot on asking the correct questions and asking the correct persons. You might have the correct and relevant set of questions but if interview the wrong set of people, you still can’t get to the root cause. The same goes with asking the wrong questions even if you have the most appropriate persons to interview.

The step of analyzing the answers and the process of eliminating those perceived as unimportant is very sensitive. As it relies a lot on human judgment alone, no matter how learned and knowledgeable the person is, he could still be subject to bias and discrimination. Critics of 5 Whys see a lot of faults in this step.

It is for this reason that the maturity, wisdom, knowledge and freedom from bias are important characteristics of the person doing the investigation. His main concern and loyalty should be aligned to the organizations goals and with nothing else.