The presumption of human error

Naturally, we respect and admire doctors. We believe that health care is scientific. We think of hospitals as places of safety. For all these reasons, it comes as something of a shock to realise that errors still play such a significant role in whether we leave a hospital better or worse, alive or dead.

The National Audit Office estimates that there may be 34,000 deaths annually as a result of patient safety incidents. When he was medical director, Liam Donaldson warned that the chances of dying as a result of a clinical error in hospital are 33,000 times higher than dying in an air crash. This isn’t a problem peculiar to our health-care system. In the United States, errors are estimated to be the third most common cause of deaths in health care, after cancer and heart disease. Globally, there is a one-in-ten chance that, owing to preventable mistakes or oversights, a patient will leave a hospital in a worse state than when she entered it.

There are other industries where mistakes carry grave consequences, but the mistakes of doctors carry a particular moral charge because their job is to make us better, and we place infinite trust in the expectation they
will do so. When you think about it, it’s extraordinary we’re prepared to give a virtual stranger permission to cut us open with a knife and rearrange our insides as we sleep.

Perhaps because of the almost superstitious faith we need to place in surgeons, we hate to think of them as fallible; to think that they perform worse when they are tired, or that some are much better at the job than others, or that hands can slip because of nerves, or that bad decisions get taken because of overconfidence, or stress, or poor communication. But all of these things happen, because doctors are human.

What the medical profession can learn from the airline industry about how to protect against human error. A riveting story about how we must build around the assumption of inevitable human error.

The passage above mirrors my own journey towards realizing that not all doctors are infallible. It may seem silly now, but as a child, I had a learned reverence of the medical profession. All the training, all the accreditation, the requirement to address them by a title all their own—“Doctor”—was blinding.

In 1997 I was back in the Bay Area and went to play pickup basketball with some old Stanford classmates at a local gym. A scrimmage game against a group of older Greeks turned heated, as such games are wont to be with the physical release of so much pent up testosterone. On one drive to the basket, I took a hard shove and went flying sideways. I landed on my left food and my left knee flew sideways an opponent's leg that was planted on the ground.

I felt a searing pain immediately and collapsed. Some teammates carried me to the sideline, and my knee immediately started swelling. I'd never felt anything like this before. Something had happened, but I didn't know what.

I crutched my way back to Seattle, stayed on crutches for a few days, and eventually got in to see an ortho. He laid me down, tugged on my leg a bit this way and that, moved my leg around, and gave me a comforting diagnosis. It was a mild sprain, I could resume light physical activity after the swelling subsided.

At the gym, on an elliptical trainer, something didn't feel right. But the doctor had done some tests, who was I to question him? The web existed, but it was much sparser than it is now. WebMD and sites like that didn't exist.

Back then, Amazon's unofficial official company sport was broomball. The popular stereotypes of technology companies being populated with a bunch of meek, gaunt, sun-deprived software developers neglect the army of MBA's with their world-conquering ambitions, the ex college jocks in business development, the crazy endurance athletes whose motor played on the field or in the office. We played at company functions, and the games felt like some form of trial by combat.

My knee still felt off, but I wasn't about to miss out on our team's broomball contest. We played on a muddy field, it was like some form of field hockey minus pads. You just had to accept that you'd leave battered, your shins a mess of bruises. We taped tennis balls to the ends of our broomsticks so as not to take out anyone's eyes.

From the start I couldn't move that well, so I hung back to play defense. And then an opponent broke loose, a herd of people chasing him, and I moved to intercept the ball. At best, with all the momentum he'd built up, I hoped to deflect the ball horizontally to give the rest of my team a chance to catch up and reset.

As I moved diagonally to meet the path of the ball, he tried to make a sharp cut, but on the muddy field, he couldn't turn enough, and both ball and opponent came sideways and collided with me.

My left leg experienced what the doctor would later call a pivot shift, where the top and lower leg came out of alignment. I fell to the ground screaming. My day was over, and I don't remember now how I drove myself home considering it was a manual transmission.

I found myself back in that same ortho's office a day later, and I told him something wasn't right, to check me again. This time, he consented to perform an MRI.

When the results came back, he was almost sheepish in sharing the news. Though he'd performed the standard Lachman Test and some other tests the last time I'd come in, in fact I did have a torn ACL. I'd been running around for weeks without my left ACL.

Needless to say, I didn't let that ortho perform my ACL reconstruction.

The first time I visited, was the ortho hesitant to order an MRI because of the expense, because I was on an HMO? Or did he just not perform the Lachman test properly? It still haunts me, but the lasting consequence was the shattering of my belief in the infallibility of doctors. I still have deep respect for the medical profession, my brother and his wife are both doctors whom I turn to again and again for advice, but nothing about medical training magically removes human error from day to day life.


If the severity of Elaine’s condition in those crucial minutes wasn’t registered by the doctors, it was noticed by others in the room. The nurses saw Elaine’s erratic breathing; the blueness of her face; the swings in her blood pressure; the lowness of her oxygen levels and the convulsions of her body. They later said that they had been surprised when the doctors didn’t attempt to gain access to the trachea, but felt unable to broach the subject. Not directly, anyway: one nurse located a tracheotomy set and presented it to the doctors, who didn’t even acknowledge her. Another nurse phoned the intensive-care unit and told them to prepare a bed immediately. When she informed the doctors of her action they looked at her, she said later, as if she was overreacting.

Reading this, you may be incredulous and angry that the doctors could have been so stupid, or so careless. But when the person closest to this event, Martin Bromiley, read Harmer’s report, he responded very differently. His main sensation wasn’t shock, or fury. It was recognition.

RELATED: Atul Gawande's great book A Checklist Manifesto.