Introduction: This investigative method aims to uncover the complex relationship between cause and effect, revealing underlying issues.
By asking 'why' repeatedly, it peels away layers of complexity until the root cause is exposed. Typically, five rounds of questioning are enough to lessen human errors like bias and assumptions, recognizing that problems don't always follow a logical pattern.
The main idea here is recognizing that while humans may not fail, processes can. So, the final 'why' inquiry aims to identify any organizational flaws within the systematic process, stressing the importance of asking 'why did the process fail?' as the final step. 

Illustration of "The 5 Why process"

Approach:
Start by identifying the problem that needs investigation.
Then, ask a series of 'why' questions, digging deeper until the root cause, often an organizational flaw, is revealed. If needed, move on to exploring why the process failed until the cause is pinpointed. 

Considerations:
This method works best when used by a collaborative team.
Clearly defining the problem and its components is crucial, shaping and influencing the analysis. The team should follow a systematic approach, supported by evidence, while verifying answers to avoid errors. Deeper insights require a fact-based analysis. 

Often, multiple root causes may emerge, requiring prioritization based on severity
to address the most pressing issues effectively. 

Advantages:  

• Simple and accessible.  
• Empowers all members of the organization to address minor issues.  
• Easily explainable logical framework to those unfamiliar with the process. 

Weaknesses:  

• Risk of overlooking multiple causes at each level and the potential for a flawed cause to compromise the rest of the analysis.  
• Challenges in determining when to stop 'why' inquiries.  
• Reliance on user knowledge, though collaboration can help overcome this limitation.  
• The non-repeatability of the '5 whys' method. 

How to Use: Use a table or the fishbone (Ishikawa) diagram to facilitate the 5 why process effectively, promoting structured analysis and comprehensive problem-solving. 

Five whys - Wikipedia 

The 5 Whys of Risk Analysis - VelocityEHS 

https://www.interviewhelp.io/blog/5-whys-analysis/