The primary reason for investigating workplace incidents is to determine their causes and prevent similar incidents from occurring again in the future.
To effectively intervene, the investigation has to report accurate and meaningful causal factors. These inform the type of corrective actions that will be taken and which control measures will be prioritized.
This is where we sometimes run into trouble. All too often, investigators settle for what seem to be the most obvious factors after taking a cursory glance at the incident details. That, or they approach the investigation with the misguided intention of establishing fault and pointing fingers, instead of identifying the root cause of the event.
To make things more complicated, most incidents result from the interaction of various causal factors.
The “Swiss Cheese” model is helpful for understanding this. Picture a stack of cheese slices standing between workplace hazards and an actual incident. The holes in each slice represents weaknesses in your control strategies. A hazardous condition might be able to pass through one of the holes (say, a leak in a chemical container) but it usually gets blocked by the slice underneath it (chemical protective gloves worn by the employee handling the chemical container). It’s only when the random holes in the individual slices happen to line up that the hazard actually translates into an incident.
Suppose, for instance, that an employee trips and falls. You could chalk it up to inattention and call it a day. If that employee had just watched where they were going, they would’ve managed to stay upright. Case closed.
But the real story is likely more complex and could also involve a number of other factors, like:
- Inadequate safety training
- An old floor mat with an edge that curls up
- Improper footwear
- Overburdened workers who are always rushing around
- Poor lighting
- Clutter and infrequent housekeeping
Chalking it all up to inattention misses the fact that a distracted worker wouldn’t have tripped if the floor mat was in good condition, might have seen the hazard if the area was well-lit, and might have been more aware of their surroundings if they had a more reasonable workload and didn’t have to hurry everywhere.
You need to know every hole in the Swiss Cheese stack to understand why the incident really happened. And you need to seal all of them up if you don’t want a similar event to happen again. A functional investigation will help you do this.
How to Use the 5 Whys
A Root Cause Analysis (RCA) is a structured approach for identifying the root causes of incidents. Some of the most widely used approaches for RCAs are TapRooT, Ishikawa diagrams, and the 5 Whys. The latter is popular for its simplicity, but it also happens to be an effective tool for identifying causes that may not be immediately apparent in the incident details.
Asking Why
The 5 Whys starts with asking and answering one basic question: “Why did that happen?”
Once you look at the situation and come up with your answer, you then ask the same question again: “Okay, now why did that happen?”
Repeat the process until you’ve asked “Why?” a total of five times and you should have a much better idea of the causes behind the incident you’re investigating.
Sorting the Causes
When all the causes have been identified, they’ll into three essential types:
In that order, they represent the most superficial and immediate causes (basic causes), all the way down to the fundamental management system deficiencies that allowed the subsequent causes to occur (root causes).
A properly conducted 5 Whys analysis should reveal causes at all levels. And in theory, asking “Why?” five times will allow you to get deep enough to reveal the root of the incident.
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What Makes the 5 Whys Method So Effective
Why go through the trouble of doing all this?
On the surface, the 5 Whys probably seems like an arduous route to reveal what the investigation team already knows. After all, you’re not gathering any new information to answer this series of questions.
Yet, it gets results. The 5 Whys is a structured brainstorming session that forces you to dig deeper, often revealing insights that wouldn’t emerge naturally.
We’re all prone to overvaluing the superficial causes because they’re concrete, simple, and obvious. But if all of our remedial actions only target those superficial factors, we’re only treating the symptoms. Those causes need to be addressed, of course, but taking care of them is not going to be sufficient. Digging all the way down to the root causes gives us an opportunity to take meaningful action to prevent future incidents.
Root causes tend to be more conceptual and involve failures of management systems. Tackling them can be a bit more challenging, but tends to be far more effective.
To see why, consider the following hypothetical example.
A company has a fatality when a worker falls to another level and strikes the ground even though he’s wearing fall protection. A month later, an incorrectly shored excavation has a minor cave-in where nobody is injured.
On the surface, those two incidents are as different as can be and probably wouldn’t even involve the same type of worker. Still, a well-conducted 5 Whys analysis might find that both incidents share a common cause. These are critical, high-hazard activities that require rigorous procedures to be both written and enforced, so what was missing? Was the person who wrote them competent? Were the operators trained? Is the responsibility for control established appropriately?
When identifying and addressing the root causes, some downstream causes can be tackled as well. In this example, the company could update their training program, reconfigure their supervision practices, and assign responsibility for checking and verifying controls. Taking these steps would naturally alleviate many other causal factors and help prevent incidents that may appear to have little in common at a superficial level.
Get the Most Out of Your Investigation
Once the investigators have completed their work, and the causes have been identified, the results should be shared across the organization.
Some organizations resist this and prefer to keep their investigations quiet, as though they reveal management failings that they’d rather keep concealed. However, excessive discretion represents a failing of its own. The reality is that employees talk, and keeping the results of the investigation under wraps can make it seem like you’re trying to sweep it under the rug. This, in turn, can make employees reluctant to participate in the workplace and report incidents, which is toxic to corporate safety culture.
Top management should be seen to be taking incidents and near misses seriously. And that means taking dedicated, demonstrable action to address causes.
It’s not just about optics, though. Doing the work to dig in and get to the root cause yields highly valuable information. Not sharing it across the organization means that too few people can learn from it.
You’ve used the 5 Whys to gain important insights. The next step isn’t to bury the results in a document – it’s to act on those findings so you can have a bigger impact on the safety of your workplace.
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