Human factors and accident investigation: avoiding the blame game
6 September 2013
Posted by: Marilyn French St. George
Like many other investigators at the TSB, I often encounter those who assume “human error” is to blame for an accident. And while I understand this reaction — it’s easy, especially with hindsight, to judge a person or an organization for failing to do something— blame is a knee jerk response that does little to promote safety for the future.
Instead, the goal of a human factors specialist is to understand the actions of the people involved, thereby making informed assessments as to whether conditions will repeat themselves or an accident will reoccur.
A simple assumption
I start with a simple assumption: that the people involved didn’t wake up that morning and plan to have an accident. Thus the question shifts from “what did these people do wrong?” to “why did their actions make sense to them at that time?” Other questions soon follow, including:
- Are other people or organizations likely to find themselves in the same situation and make the same decisions?
- What factors in the work environment led to these actions?
- What can be put in place to change those factors for the better?
Typically, accidents happen when actions and circumstances come together at just the right time. Many of the variables or changes can seem insignificant at the time, with people often reporting that they did little different from any other day. To get to the bottom of things, I focus on how work is supposed to be carried out (standard operating procedures, training manuals, etc). Then I compare it to how work really gets done, and again to what happened on the specific day in question.
Understanding the adaptations
Understanding these differences, or adaptations, is critical—it helps me understand the drivers for the choices people make. For instance, as adaptations are identified, we assess the extent to which they have become the “unofficial” workplace standard, and how these new (and possibly undocumented) adaptations impact the workplace. For example: are other employees aware of the changes? Is management?
The boundaries of human capacity
In any workplace, people are always juggling a variety of tasks—and with differing levels of success. Human factors investigators assess all relevant aspects of human performance: perception, attention, memory, and planning—all to determine whether the demands of the job exceed a person’s ability to perform a task reliably. We use the results from established research studies to define the boundaries of human capacity and then develop a compelling argument to explain why the event happened.
Hopefully, by identifying the factors that led to an accident (or which might increase the risk of another accident taking place), we can better understand how our complex transportation system really works. And while there is never an “ah-ha moment” in which a single cause is identified as solely responsible, our work helps shine a spotlight on the management and operational characteristics that place excessive demand on people.
Marilyn is a Senior Human Factors Analyst and, after four years at the TSB, she will soon retire. She is a big-picture thinker who loves the details. For fun and (not so much) profit she works with glass and wood to create objects of enduring beauty.
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