5 why root cause analysis [w/example]

The 5 why root cause analysis technique originated at Toyota Motor Company as a way to improve inefficiencies in manufacturing processes.

Today, businesses across all industries use the 5 whys to investigate safety incidents, research process improvement opportunities, and more. Every EHS professional should have this technique in their toolbelt for deep diving the operation and reaching new milestones of overall performance.

What is 5 why analysis?

5 why analysis is a technique for finding the root cause of a problem.

The basic idea is this:

Ask yourself “why did this happen” at least five times to find the root cause of a problem.

The goal of this approach is to challenge you to go past your initial assumptions. Oftentimes, what looks like the root cause is actually just a surface issue. To understand the systems or behaviors that led to an outcome, you need to be sure you’ve considered each level of the problem.

This technique provides an effective framework to deep dive EHS incidents, especially when the safety team can’t immediately identify what went wrong.

5 steps to follow

Always start a 5 why root cause analysis by stating the problem that you want to deep dive.

Then, proceed to ask yourself why the problem exists five times in a row (at minimum). With each “why,” you should get more specific and ultimately closer to understanding what happened.

Here are the basic steps of performing a 5 why incident investigation:

STEP 1: Define the problem. What was the negative result of the workplace incident?

STEP 2: Ask “why” at least five times to narrow down the root cause.

STEP 3: Decide the root cause once you’re finished asking “why.”

STEP 4: Find a solution to protect employees against the root cause in the future.

STEP 5: Take action to implement your chosen solution and monitor its effectiveness.

The last step is crucial—if you don’t follow up on your corrective actions, it’s very likely that you’ll end up with the same problem again in the future.

When to use the 5 whys

The most common use of the 5 whys is to deep dive EHS-related issues, such as:

• Process hazards
• Common workplace injuries
• Accidents
• Property damages
• Safety culture and leadership issues

This simple approach can help managers better understand the policies, equipment, procedures, etc. that have contributed to workplace hazards or inefficiencies. While the approach remains the same, you’ll find that each incident requires unique solutions.

At times, your corrective actions may tackle the operation itself (things like reorganizing workstations or swapping out equipment). Other times, the solution may require you to address individual behaviors or the site’s culture.

Consider this 5 why analysis example that you can use as a reference for your own investigations:

The biggest mistake to avoid

When it comes to incident investigation, the biggest mistake you can make is to assume a root cause without doing any sort of deep dive.

You might be surprised, but the best time to do a 5 why root cause analysis is when you think you know the reason for an incident right away.

Oftentimes, quick assumptions and lack of deep dive can actually perpetuate workplace problems. After all, if the cause was so obvious, why was it allowed to persist?

What you’ll notice when you perform a 5 why analysis is that no two incidents are the same. For example, you could have two separate PIT incidents, in the same exact location, on the same day, and still come up with different causes.

That’s why separate investigation of each incident is so important—it prevents incorrect assumptions from dictating incident follow-up procedures.

Causes of safety incidents

Some of the most basic, top-level causes of safety incidents include:

• Insufficient training
• Behavior-based safety issues
• Workstation setup (5S, process flow, etc.)
• Lack of preventive control measures (guards, lockout systems, etc.)

When you go further, however, you can almost always find multiple improvement opportunities to tackle. A big sign that you’re not performing quality incident investigations is if all your corrective actions fall along the lines of punishing or coaching employees.

It’s so easy to convince yourself that workers’ behavior is the main issue. In reality, however, you have to ask yourself “why was the employee allowed to make an unsafe decision at all?”

There is always a way to direct human behavior towards the only safe option in a given situation. You just have to find the point in the process where the choice to go against safety protocols exists. If you can find this point using the 5 why root cause analysis technique, you’ll have a better chance of making a change that actually prevents the incident from happening ever again.

Track root cause analyses

If incident investigation and/or process improvement are a big component within your operation, you should consider how you’ll manage and track what you uncover.

Without some sort of tracking system, you may find yourself repeating the same issues over and over again. A comprehensive approach to the 5 whys must include a way to verify that corrective actions are complete following a deep dive.

At Frontline Data Solutions, we offer a corrective action tracking system, Frontline ACT, that helps teams document incidents, projects, and more. Features within the system allow you to delegate action items to different members of your team and ensure they’re completed on time.