There is a horrifying term in aviation, called the death spiral, or the graveyard spiral, where a pilot believing that they are flying steady with the wings level is actually caught in a downward spiral, sometimes ending tragically with impact on the ground.

William Langewiesche wrote about this in an old essay for the Atlantic, called The Turn, and describes it in detail:

“In clear skies they would never misjudge a bank as the tilting of the earth, but with their view restricted to the abstractions of the instrument panel they sometimes do just that: when the airplane banks, they perceive the motion as a movement of the artificial horizon line across the face of the instrument. … Reacting instinctively to the indication of motion, they sometimes try to raise the line as if it were a wing. The result of such a reversal in such cases is murderous. Pilots steer to the left just when they should steer to the right, and then in confusion they steer harder. While cruising calmly inside clouds, I have had student pilots suddenly try to flip the airplane upside down. These were perfectly rational people, confronted by the turn.” “The airplane flies in ever-steeper circles and either disintegrates from excessive speed or hits the ground in a screaming descent.”

What Langewiesche writes about in The Turn is that there was a transition, in flying, from the daredevil fly-by-feel pilots to those that trusted not their instincts but their instruments, and that it was this slow transition towards understanding the physics of flight and the limitations of our own senses that made air travel safe and turned it into what it is today.

On the web today, we are seeing a similar transition happen. People are measuring user engagement more closely and more granularly, and there are similarly more tools and instruments to allow us to monitor mouse movements, clicks, and behaviors. The rise of the growth hacker is a sign of the real value being assigned to being an expert at instrumentation.

And for an industry defined by growth, by growth at all costs, this is an exciting thing. But at the same time, there are a few cases where companies lose sight of their horizon. Some sites steadily degrade their user experience (and their users) in order to boost conversion rates for signups. Others lean on email or notifications, and upon seeing bumps from metrics like page views, lean harder and harder.

It’s seductive, seeing easy gains in an otherwise exhausting process. But it is also dangerous. Interstitials, engorged call to actions, points earning — sometimes these changes focus and simplify the product, and other times they strain it, turn the product’s voice from calm to grating, cause the product to lean in too close, interrupt people mid sentence, hold handshakes too long. Sometimes companies emerge from the clouds caught in a screaming descent.

I have been thinking about this as the user engagement death spiral, a state where a company, with all of their tools and instruments, has become caught by the numbers and the numbers alone. And this death spiral, rather than professionalize the industry like flight, demeans it. The difference here is that people’s behaviors and interactions do not have a defined physics, no set of rules to instrumentalize. And so escaping these death spirals then might require what pilots had to give up: a sense for which way is up, an instinct for where the ground is.