The 5 Whys of Root Cause Analysis

Recurring problems cause pain for any business and are often symptoms of deeper issues. Utilizing the 5 Whys of root cause analysis allows these deeper issues to be uncovered and addressed. It also mitigates the tendency for shortcuts or quick fix options that may be tempting, but usually do not identify the real causes of the issues and end up wasting resources.

The 5 Whys of root cause analysis offer a lot of versatility; they can be used for troubleshooting and quality improvements, but fit best for cause identification and problem solving. The only exception would be complex problems that may have multiple causes where another method can fit better.

The 5 Whys analysis leads to the root cause of a problem. It is best to try using the 5 Whys first before diving into a more complicated approach. However, it is very flexible and works well with other methods like root cause analysis and is utilized in lean manufacturing techniques to discover and eliminate wasteful operational practices and in the analysis phase of the Six Sigma methodology.

Following a set process is an optimal approach:

Gather a team of the people most familiar with the problem. Appoint a facilitator to manage the team, keep them on task and document the counter measures, preventative and corrective actions identified.

Try to recreate the problem to observe and document what the team agrees is happening. For example, “Cell B missed production targets last month”. Use a whiteboard or sticky notes to write the statement down and document answers from the team to the 5 Why questions.

The first of the 5 Whys is to ask the team why Cell B missed production targets last month. Brainstorm for answers that were observed during the problem recreation or factual observations from related processes, procedures or activities. It sounds easy, but there are a large number of possible causes in this early stage and the focus needs to be on what happened, not what might have happened.

The team members usually come up with a handful of plausible reasons, but most answers are rejected as hypothetical or not relevant. Being selective is important to avoid wasting time and resources chasing down dead ends. Write the plausible answers on the whiteboard below the problem statement. Be as specific as possible – for example, stating one of the five machines was down for maintenance for one week is better than machine down for maintenance.

The next steps would be taking each of the plausible reasons one by one and asking 4 more Whys to drill down to the root cause of the problem.

Why was one machine down for maintenance for a week this past month? Answer: it was an unplanned mechanical failure. What caused the mechanical failure? Answer: A bad spare part was installed in the machine that morning. Why was a bad spare part used in the machine? Answer: Because it was the only part of that type in the inventory and ordering new ones takes several weeks. Why was there only one part left in the inventory? Answer: Because the procurement department had failed to restock the part last month.

Once the root cause is understood, counter measures along with preventative and corrective actions can be identified, reviewed and implemented to address the problem. Consider the following when reviewing the possible options.

Counter Measures:
Actions that meet the problem or failure head on and immediately. Temporary steps that can be implemented right away to relieve the pressure until more substantial actions can be taken.

Preventative Actions:
What can be done to prevent the problem happening again? This second level activity acknowledges there is no corrective action established yet, but the need exists to implement processes or procedures to mitigate or eliminate recurrence.

Corrective Actions:
When the true root cause is identified, a corrective action is needed. This is a permanent solution to the problem. If the corrective action cannot eliminate the chance of a failure, it is not corrective action.

Please contact us for questions about the 5 Whys or find out more about our lean root cause analysis services for companies in the Philadelphia, PA region and across the country.

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