RCA 5 Whys: A Simple Yet Effective Analysis Tool

The Five Why analysis as an RCA tool

As an RCA technique, the Five Why analysis helps to investigate an incident and diagnose the root of an issue without having to do an extensive root cause analysis. It is used proactively for investigations like near-miss incidents and non-critical equipment failures.

(Read more about RCA in our eBook 'Four Steps to Improve Your Root Cause Analysis Program')

The technique can be used by following these simple steps:

#1 Define the problem clearly and simply

Build a knowledgeable team with members who are involved with the specific project or equipment you are investigating.

• It is important to assemble a knowledgeable team that includes members involved with the specific project or equipment being investigated.
• The problem being analyzed should be singular and clearly defined to avoid confusion during the analysis process.
• Responses gathered during the Five Whys analysis should focus on systems rather than individual errors.

Use this team to agree on a clearly defined problem statement to get closer to the root of the issue. It is critical to agree on the definition of the problem and to focus on errors and inefficiencies within the processes.

#2 Clarify the Evidence

Outline the specifics of the problem and collect evidence from the incident. Evidence is information that is both valid and quantitative. Examples would be data logs, witness statements, instruments, physical symptoms, and observations.

Note: Do not stop at human error as this is usually the symptom of larger problems within the organization.

#3 Conduct the Five Why analysis

Once the evidence is outlined, ask the question 'What could have caused this issue to occur?' and record the answer with tangible evidence. An effective way to gauge whether you are focusing on the right problem is to ask whether the problem will occur again if the most recent answer to the problem is corrected or if anything else can produce the same problem. Continue with this causal pathway until you get to the root of the problem – typically this is a gap in processes within the organization.

Note: Not every case will reach the root cause at the fifth "Why" because a problem may require going deeper into the causal pathway. It is appropriate to continue until the root cause is identified.

#4 Design the right solutions for lasting process improvements

Once you reach the root cause of the issue, you can begin to design solutions that will remedy the issue.

A solution is considered appropriate if it:

• directly addresses the issue
• prevents a reoccurrence of the issue
• is controllable
• helps achieve organizational goals and objectives
• does not create a ripple of more problems

With the solution in place, a detailed implementation timeline can be made with clear roles and responsibilities. This clarification ensures lasting improvements to the process with significant risk reduction.

Five Whys example

Problem Statement/Incident

A machine critical to production is leaking oil despite receiving regularly scheduled maintenance and having a new seal installed.

Infographic: 'Five Why' analysis flow chart

Why #1: Why is the machine leaking oil?

The seal appears to be corroded, therefore losing integrity, leading to a small leak.

Why #2: Why is the seal corroded?

There appear to be non-native particles in the oil, which could be causing damage to the integrity of the seal.

Why #3: Why are there non-native particles in the oil?

The filter that was installed during the most recent scheduled maintenance is not functioning properly and is letting through the non-native particles.

Why #4: Why is the filter not functioning properly?

The filter did not align with OEM specifications, leading to a poor fit that allowed non-native particles to permeate. These non-native particles eventually led to the seal corroding and causing a leak.

Why #5: Why was the right filter not replaced?

There is no management of change for filter changes – therefore the tech who performed the maintenance did not have all the information necessary to avoid the small mistake.

Root Cause: The true root cause is that there is no management of change for seal changes.

Actions

• Immediate action: Replace the filter with the OEM recommended mesh filter
  • Interim action: Input corrections to the reorder specifications so that it keeps into account the proper seal and filter
  • Root cause Solution: Review and address management of change deficiencies

Once these steps are complete, the incident should be closely monitored to ensure the right solution was implemented.