Randomness is Often Not Random

In statistics, what we often identify as randomness in data is not actually random. Bear in mind, I am not talking about randomly generated numbers or random samples. Instead, I am referring to events about which data has been recorded. We learn of these events when we examine the data. We refer to an event as random when it is not associated with a discernible pattern or cause. Random events, however, almost always have causes. We just don’t know them. Ignorance of cause is not the absence of cause.

Randomness is sometimes used as an excuse for preventable errors. I was poignantly reminded of this a decade or so ago when I became the victim of a so-called random event that occurred while undergoing one of the most despised medical procedures known to humankind: a colonoscopy. In my early fifties at the time, it was my first encounter with this dreaded procedure. After this initial encounter, which I’ll now describe, I hoped that it would be my last.

While the doctor was removing one of five polyps that he discovered during his spelunking adventure into my dark recesses, he inadvertently punctured my colon. Apparently, however, he didn’t know it at the time, so he sent me home with the encouraging news that I was polyp free. Having the contents of one’s colon leak out into other parts of the body isn’t healthy. During the next few days severe abdominal pain developed and I began to suspect that my 5-star rating was not deserved. Once admitted to the emergency room at the same facility where my illness was created, a scan revealed the truth of the colonoscopic transgression. Thus began my one and only overnight stay so far in a hospital.

After sharing a room with a fellow who was drunk out of his mind and wildly expressive, I hope to never repeat the experience. Things were touch and go for a few days as the medical staff pumped me full of antibiotics and hoped that the puncture would seal itself without surgical intervention. Had this not happened, the alternative would have involved removing a section of my colon and being fitted with a stylish bag for collecting solid waste. To make things more frightening than they needed to be, the doctor who provided this prognosis failed to mention that the bag would be temporary, lasting only about two months while my body ridded itself of infection, followed by another surgery to reconnect my plumbing.

In addition to a visit from the doctor whose communication skills and empathy were sorely lacking, I was also visited during my stay by a hospital administrator. She politely explained that punctures during a routine colonoscopy are random events that occur a tiny fraction of the time. According to her, these events should not to be confused with medical error, for they are random in nature, without cause, and therefore without fault. Lying there in pain, I remember thinking, but not expressing, “Bullshit!” Despite the administrator’s assertion of randomness, the source of my illness was not a mystery. It was that pointy little device that the doctor snaked up through my plumbing for the purpose of trimming polyps. Departing from its assigned purpose, the trimmer inadvertently forged a path through the wall of my colon. This event definitely had a cause.

Random events are typically rare, but the cause of something rare is not necessarily unknown and certainly not unknowable. The source of the problem in this case was known, but what was not known was the specific action that initiated the puncture. Several possibilities existed. Perhaps the doctor involuntarily flinched in response to an itch. Perhaps he was momentarily distracted by the charms of his medical assistant. Perhaps his snipper tool got snagged on something and then jerked to life when the obstruction was freed. Perhaps the image conveyed from the scope to the computer screen lost resolution for a moment while the computer processed the latest Windows update. In truth, the doctor might have known why the puncture happened, but if he did, he wasn’t sharing. Regardless, when we have reliable knowledge of several potential causes, we should not ignore an event just because we can’t narrow it down to the specific culprit.

The hospital administrator engaged in another bit of creative wordplay during her brief intervention. Apparently, according to the hospital, and perhaps to medical practice in general, something that happens this rarely doesn’t actually qualify as an error. Rare events, however harmful, are designated as unpreventable and therefore, for that reason, are not errors after all. This is a self-serving bit of semantic nonsense. Whether or not rare errors can be easily prevented, they remain errors.

We shouldn’t use randomness as an excuse for ongoing ignorance and negligence. While it makes no sense to assign blame without first understanding the causes of undesirable events, it also makes no sense to dismiss them as inconsequential and as necessarily beyond the realm of understanding. Think of random events as invitations to deepen our understanding. We needn’t make them a priority for responsive action necessarily, for other problems that are understood might deserve our attention more, but we shouldn’t dismiss them either. Randomness should usually be treated as a temporary label.

Take Care,

5 Comments on “Randomness is Often Not Random”

By Sven Heinrich. March 13th, 2018 at 8:59 am

That’s really an awful experience. Seems to me that the hospital administrator was trying to prevent you from suing the hospital with this questionable argument.

By stephenfew. March 13th, 2018 at 2:56 pm

Yes, Sven, were it not for fear of a lawsuit, I doubt that I would have not received a visit from the hospital administrator. This statistical malfeasance was motiviated by the hospital’s self interest.

By Nate. March 15th, 2018 at 7:03 pm

Ouch! Our family has been dealing with the medical system for over two years now and it’s a nightmare. Medicine is in the throes of the reproducibility crisis…

I would change one thing in your post about events almost always not being random – they are Always not random. There is no such thing as a random event with no cause – the term random is usually simply shorthand for “unknown cause”. If we know all (and I mean all) of the initial conditions, we could always predict a given event. Since we never have all the initial conditions, we have to speak in probabilities. Given Evidence X, the probability of event Y|X is such and such.

Even ‘random numbers’ can be regenerated and perfectly predicted if we have the initial conditions and the algorithm.

There appear to be a few events where we have no insight into the cause, for example, quantum events or radioactive decay. It appears that the information on the cause of these events is blocked from us, so the event is unpredictable. But the event is not *caused* by randomness.

By stephenfew. March 15th, 2018 at 7:30 pm


I considered saying that randomness is never actually random, but chose to exercise caution instead. It’s possible that true randomness (i.e., events that lack a cause) exists, but also possible that, what appears to be random always has a causal explanation, even though it eludes us. The answer is currently beyond our reach.

By Nate. March 15th, 2018 at 8:30 pm

I understand the sentiment. One can go down a deep rabbit hole of epistemology and semantics around what a ’cause’ is.

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