Editorial: Is Predicting Black Swans a Worthwhile Endeavor?

My earliest foray into chemistry was somewhat hapless. One of my first science projects in third grade involved testing the pH of a few common household liquids and arranging them from most acidic to most basic. We tested liquids such as water, lemon juice, dish soap, and milk. For some odd reason, I went into the project assuming that milk was a base. I remember dipping the red litmus paper in the milk over and over again, and becoming more and more confused that it wasn’t turning blue. I didn’t try dipping the blue litmus paper in the milk — if I had done this, it would have been a clear indicator that milk is in fact mildly acidic. I don’t remember why I assumed that milk was basic, but it was likely something I misheard from the teacher. Eventually, I moved forward with the experiment with the assumption that my red litmus paper was somehow malfunctioning.

My ill-fated science experiment is a prime example of confirmation bias: the tendency to process information in a way that conforms to a person’s pre-existing beliefs. In our cover story this month, author Will Sharpe, a consultant at Kent, writes, “confirmation bias encourages a naïve projection of the future based on the past” (pp. 28–33). Cognitive biases like confirmation bias can lead engineers and process safety experts to misinterpret information and form inaccurate conclusions — causing them to simplify or outright dismiss the possibility of “black swan events.”

A black swan is an unexpected event with major consequences that is often deemed unpredictable. In hindsight and with the benefit of rationalization, though, many so-called black swan events are unavoidable — or even inevitable. For example, some people believe that the COVID-19 pandemic is a black swan event, says Sharpe. “Yet, when you assess the predictability of such an event, that argument is flawed,” he writes.

In his Forbes article “Was COVID-19 a Black Swan Event?,” John Drake (Univ. of Georgia) writes, “since the 1957 influenza pandemic, on average, one pandemic has appeared each decade through COVID-19… So, if the future is anything like the past, we can expect a new pandemic disease about once a decade.” Even Nassim Nicholas Taleb himself, the man who first coined the term black swan, has stated that the COVID-19 pandemic was in fact largely predictable and therefore not a black swan.

Sharpe’s article confirms that an engineer’s job is not to predict black swan events during process hazard analyses (PHAs). Instead, PHA teams and process safety practitioners should be aware of humans’ natural inclination to dismiss unlikely events, just as world leaders likely oversimplified the potential for a pandemic of such severity. An awareness of cognitive biases might allow engineers to identify “grey swans” — i.e., unlikely events that lack randomness.

My confirmation bias about something as trivial as milk led to my own mini grey swan event: scoring a B– on a major science project. This could have easily been avoided with some critical thinking and careful adherence to the teacher’s instructions. By breaking down confirmation biases, engineers can be better aware of the grey swan events on the horizon.

Emily Petruzzelli, Editor-in-Chief