Information & Training. | TQM. Total Quality Management.
Five Why’s AnalysisFive Why’s Analysis is a very effective and consequently widely applied technique to problem solving and continuous improvement. via the identification of the root causes of problems, the understanding of the causes and consequently the identification of appropriate actions to permanently eliminate the problem causes.
Five why’s is a sequential “cause-effect” analysis, where those tasked with addressing a problem sequentially ask how an event arose, e.g. why did the failure arise, why is the quality specification not being achieved, why are we seeing unexpected process equipment shutdowns, why has the yield decreased. These previous examples all tend to relate to negative events, equally, five why’s problem solving can relate to positive events, e.g. process variability has improved, why? Process throughput has increased, why? Absenteeism has decreased why? ….
Five why’s is a method for helping us understand why events arise or why we are seeing change occurring. It is a relatively easy to understand, yet very powerful root cause analysis and improvement methodology. The key focus of five why’s is to move away from seeing and fixing the symptoms towards identifying, understanding and addressing the root cause of an event.
Applying the Five Why’s Analysis problem solving method.As outlined previous the five why’s is a sequential “cause-effect analysis”. Once a problem has been identified or some form of event occurrence needs to be understood, the question “why” is asked.
Why has the problem arose?
Why is this event occurring?
Once why is asked a number of potential causes may be identified. For each of these potential causes the question “why” is this cause arising is again asked. This process is repeated for each potential cause until no further why’s can realistically be asked. At this stage the root cause of the original problem or event occurrence may have been identified.
Five why’s analysis is best performed by a team consisting of a range of skills and experiences. This creates a brainstorm environment, where innovative and novel suggestions can arise which will facilitate the identification of potentially hidden root causes.
When a team is seeking to understand and solve a problem, by asking the why question approximately five times, and having identified five realistic causes, experience tends to indicate that the team will be close to the root cause. Asking why five times is often seen as a sufficient level of investigative depth, however, the team will need to apply the five why rule based on their experience and the level of complexity associated with the problem being investigated and may decide to continue well past asking why five times.
The five why root cause analysis tool is widely accredited to the founder of Toyota, Sakichi Toyoda (1867 – 1930), who promoted the methodology as a means of driving product and process improvement via ensuring problems were effectively and permanently addressed where they arose within the Toyota process, for example product deficiencies, process failures, accident investigation, customer complaints, poor yields, etc…
Establishing and performing a Five Why problem solving Analysis.1st stage:
Identify the problem or task to be achieved. The objective must be clearly defined and documented and must be clearly understood by those tasked with performing the five whys investigation.
Assemble a team to perform the investigation. The team members need to be carefully selected so that they can provide a broad range of experienced inputs. Additionally, one of the benefits of the five whys process is the learning element. Therefore, select the team based on two approaches, one is to have team members who can contribute the most to solving the problem, i.e. members with good process knowledge, who appreciate the problem, etc., but also select team members with a view to improving their understanding of the process for future improvement efforts. It may be a good idea to introduce a new member of the organization into the five why team so that he/she gets to learn about process operations.
Start asking the why question. Why does the problem arise? Why has this event occurred? Write down the answers received. This is effectively a form of brainstorming, therefore, suggestions should not be dismissed, but should all be considered. When writing the suggested answers, i.e. the potential causes, write them on a clear display board, white board, etc., to ensure all are clearly visible.
If the answers received don’t indicate a potential root cause, then for each answer (cause), ask why again. This will result in a range of further potential causes. Each of these new potential causes will again be recorded onto the board and linked to their parent causes. The team will briefly discuss each potential cause suggested to ensure there is good understanding of why the cause may be contributing to the original problem.
The five why team will continue this process until there is a strong opinion formed within the team that the potential root causes may have been identified. The number of iterations may greatly exceed five times, however, that should be seen as a positive as it indicates that the team are striving to work down through the operation of a process with a view to truly understanding and identifying the root causes.
The team will now be left with a range of potential root causes. These should be extracted and discussed. Some of the potential causes may be excluded after review, while a number of others will remain. These then become the focus of an implementation phase.
The team has now identified potential root causes of the original problem.
Information & Training. | Total Quality Management Tools and Techniques …
- Continuous improvement utilizing Analytical Techniques.
- 5 why’s analysis
- Process Flow Diagrams/Flowcharts/Process Mapping
- Check sheets /Check Lists
- Run charts
- Scatter Diagrams/Scatter Plot
- Cause and Effect/Fishbone/Ishikawa Diagrams
- Identifying sources & causes of variation
- Control/Shewart Charts/DPU Charts
- Cpk and Ppk Analysis
- Pareto Analysis
- Bottleneck Analysis
- Etc. Etc.
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