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How Our Innate Safety Traits Can Predict Human Error

February 21, 2018

iStock-918969074.jpgWhen someone gets hurt, where does the problem lie? The human or the system? It’s in a safety professional's nature to seek the underlying cause of an event, but a more useful question to ask might be:

How can we best predict when and where our employees are at risk, and how do we best equip them to avoid injury?

In last week’s post, I reviewed the recent events that have brought Amtrak back into the spotlight. These events remind us all that humans are not infallible. However, we should not ignore the other side of this matter, which is the research showing that injuries are not equally distributed across the population. Certain individuals are much more likely than others to be involved in safety incidents, even after accounting for job experience, industry, and job type. Why? Because their unique SafetyDNA® profile predisposes them to not only engage in more risky behaviors, but to commit more frequent human errors.

Let’s take a closer look at these important connections between traits and behaviors. Based on the work of James Reason on human error, we can classify errors into three categories: slips, lapses, and mistakes.

  • Slips are instances where we do something we did not intend to do, like accidentally grabbing the wrong type of nail or shifting the car into reverse instead of drive.

  • Lapses occur when we forget to do something or lose track of where we are during a task, such as forgetting that you have your safety glasses on your head or not seeing a red light because you were distracted.

  • Mistakes arise when a person takes the wrong action, believing they were doing it correctly. An example is being unable to pay for your items at a store because you were certain they accepted credit cards when they only take cash.

    • Violations are different in that they are deliberate deviations from the correct action. But they are related to human error because they ultimately fall under the broader category of human failure. We have all committed violations in our life, such as knowingly driving over the speed limit.

Now that you understand the nature of human errors, let’s consider how they relate to the innate safety traits within all of us. If we map these types of errors onto the SafetyDNA factors, we can see some clear connections.

Typical Behaviors


People who are low in Control often leave things to chance without proactively planning. Mistakes are often due to lack of proper planning or preparation. If you don’t take the time to learn and review the correct procedure before starting a task, you are more likely to make a mistake because you don’t have all the information you need.


Awareness is the most important factor related to lapses. Individuals with lower levels of this ability are exponentially more likely to forget things, lose track of a situation, or get overwhelmed when trying to multi-task, and this is what often leads to a lapse error.


Clearly this is where violations fit in. Individuals that are less rule-bound in terms of their personality tend to see rules as just guidelines and often bend a rule if they perceive little risk of injury or being caught.


People who are low on Caution are a lot more comfortable with risk than others. This often leads to rushing, which often leads to mental slips, where something is done incorrectly or incompletely.

Did anyone come to mind as you read through the table above? If you really think about it, you can probably think of someone you know (and it could be you) who is more prone than others to these types of errors. For example, can you think of someone you know who:

  • Always seems to procrastinate and is often unprepared?

  • Seems to forget things, misplace their belongings, or zone out a lot?

  • Likes to take shortcuts or seems to think they are the exception to the rule?

  • Tends to make somewhat careless errors because they rush into things?

While seemingly small, all the examples above can make the difference between a relaxing trip and a life-altering crash. This is especially true in the case of high velocity trains, a high-exposure job we started exploring last week. What happens when an engineer makes a mistake or has a lapse that would have few repercussions if s/he were an office worker?

Errors have very different implications when working in a high-exposure environment. We know now from research in Industrial Psychology that a person’s natural trait levels on each of these factors predicts how often they engage in many of these behaviors. So why should we assume that every employee has the same probability of making errors? One train engineer may struggle the most with lapses, such as the one that occurred in the Philadelphia crash in 2015, while another engineer may have incredible attention and focus but feel very comfortable taking risks, such as going twice the speed limit around a bend – perhaps this was the case in the Dupont crash a couple of months ago? And yet, another engineer may be most at risk because of how they interpret safety rules, such as not texting while operating a train.

As a safety professional, this is exciting news. If we combine this important psychological piece with what we already know about risk assessment and mitigation, we get a more complete picture of exactly what determines a person’s risk in different situations. We can combine our knowledge about the risk associated with a specific work environment with data on how the person will react and work in that environment. For example, we typically look at two main variables when calculating risk: likelihood of an event or exposure occurring along with the severity or consequence of that event, if it occurs. This gives us the following formula:

Risk = Likelihood x Severity

But if we add the aspect of SafetyDNA, which tells us the relative likelihood of an individual committing certain types of human error, we get a formula that looks like this:

Risk = Safety Profile x Likelihood x Severity

How could this work in practice? Here’s a simple example:

  • Frank is a maintenance technician at a manufacturing company. He often grinds or cuts metal pipes and components. Later today, Frank will be working on a piece of metal that will be tough to cut.

  • His SafetyDNA profile tells us that Frank has high personal exposure when it comes to Rules, meaning that he will bend rules if he feels the risk is minimal or if the rules make the job too difficult. He has been known to remove his safety glasses at times to “get a better look” at where he is cutting and was seen removing the guard on a cutting tool before.

  • Based on your risk assessment data, you know that the risk of an eye injury or laceration is very high without the required PPE, especially since this job requires a substantial amount of cutting. But you also know that this custom piece of metal will make it tempting for Frank to remove the guard and take his safety glasses off at times.

  • While the risk index would be moderate when assuming he wears PPE, if we factor in his safety profile, we now see that the risk index of that task is elevated because he will be tempted to take a shortcut and thus not fully utilize his PPE or the safety guard throughout the job.

We can now be more proactive and targeted in how we support Frank. We can do many things, such as:

  • Talk specifically about safety policies for cutting and grinding during the morning safety meeting, with specific focus or examples of why those policies are in place.

  • Help Frank come up with a simple game plan of behaviors he should utilize if he is tempted to take a shortcut, such as taking a quick mental break, asking a co-worker to help keep him accountable, or thinking of his family.

  • Meet one-on-one with Frank before he begins this task, and remind him up front that he will likely be tempted to bend a rule today, but emphasize to him that his safety is more important to you than the customer.

These are just a few simple things that we can do to better address the specific types of errors a person is likely to commit in specific situations. By looking at both the task and the person doing the task, we can “calibrate” our employees to safely manage the exposures they will encounter on the job.

safety moments

Esteban Tristan, Ph.D. Esteban Tristan, Ph.D. is the Director of Safety Solutions at PSI. He manages the development and implementation of all safety solutions and services, which address some of the critical challenges faced by organizations today in workplace safety.