An approach to problem solving that is popular with Six Sigma1 and regulatory mindsets says you cannot find a permanent resolution to a processing error or equipment failure until you identify its “root cause.” This mindset implies that every problem, every failure, is the result of a causality chain that leads backward and down to a single source. The presumption is that you must find and eliminate that root cause in order to put things right. Any attempted fix which does not address and include the root cause is doomed to fail and serves as only a short-term, cosmetic, feel-good, band-aid solution which will allow the problem to resurface some minutes, weeks, or years later.
This approach makes sense in terms of process analysis and error trapping, dealing with temporal and ephemeral situations, which is the true realm of Six Sigma. The difficulty begins when you try to apply that level of analysis, that particular hammer, to every problem in your life, assuming that you’ve just found a nail.
We had an experience of this recently with the parking garage at our condominium. The garage is a huge structure made of reinforced concrete, three levels deep, able to park about five hundred vehicles. It’s an old structure, built almost forty years ago. Over this time the concrete has cracked and water has entered from leaks in the roof structure, from rain trailed in by car tires in the winter, and from some historic leaks in the rooftop swimming pool which have since been fixed. The result in some areas is spalling—shallow pits—in the concrete, white salt-like deposits on its surface, some exposed rebar, and rust stains. This damage has caused concern among the homeowners for the overall integrity of the structure, and the condo association has paid a concrete expert to examine the problem areas and propose repairs.
After much probing, mapping, testing, and chemical analysis the expert reported no major issues with the structure but recommended patching the spalls, routing out and sealing the cracks, applying a surface finish to the exposed concrete, and other measures that combine damage repair with preventive maintenance. He explained that concrete naturally contracts and cracks as it sets, and that water gets into the cracks, carries salts with it, and causes the rust.
That answer satisfied most people, but not a minority who want to know the root cause of the problem. The answer that water getting into cracks was the cause of the spalling, salt deposits, and rust stains has not been good enough. They want to get down to the core of the problem and feel that any fix that doesn’t address an underlying problem is doomed to fail.
And that is why today I’m thinking—brooding actually—about root cause analysis. If you must name a root cause, then was the garage badly built from the beginning? No, because the concrete expert, who is also a structural engineer, found no fault with the original design nor with its implementation during construction. Was the concrete mix or the pouring technique faulty? No, because his testing showed the concrete’s composition and strength actually exceed specifications. Was the rebar badly designed or installed? No, because the steel is still in almost perfect shape.
If you had to find a root cause for the failures in the garage, you would have to say it was built in an area that gets rain for half the year—when California isn’t experiencing a drought—rather than on a dry, high desert plateau, and it was built of concrete and steel instead of less permeable and more lasting materials like glass and titanium. Also, the condo association has failed in recent years to provide a maintenance program that might have found and sealed new cracks as they developed, repaired the pool leaks in a timely fashion, and applied a waterproof coating to all surfaces of the exposed concrete slab.
That is, once the garage was completed forty years ago, the owners made the untested assumption that it was a permanent and imperishable structure, requiring no further work and expense, like the Pyramids at Giza. Concrete and steel are supposed to be immortal, aren’t they?
You wouldn’t make such an assumption about something small and mechanical, like your car or a bicycle. They have moving parts which need regular oiling and adjustment. They have parts subject to abrasion and wear, like tires and brake pads, which need regular replacement.2 If you viewed the wear and tear of engine components and the wearing out of tires and brakes as a process failure and looked for a root cause, you would have to conclude that the source of the failure was not having made the machine out of magical, incorruptible, imperishable materials that do not yet exist in human technology.
Although a building or a structure—like our condo garage—looks solid and permanent, it is actually a type of machine. Cars driving into and out of it, bumping over expansion joints, and braking and turning, all create vibrations and stresses that move and shake the underlying fabric of concrete and steel. Water dripping off the cars, blowing in from outside, or coming through unpatched leaks in the roof will do its inexorable work of leaching chemicals out of the concrete, rusting the steel, and weakening that fabric. Heat makes the structure expand by a few millimeters or so during the summer, and cold makes it contract during the winter. And the minor temblors of a seismically active area add their own stresses. The structure is a machine that works against itself and gravity all the time.
The takeaway from all this, and the point of my musing, is that everything is subject to wear and tear, to the eroding processes of time, weather, and use. Even the Pyramids bake in the noonday sun, freeze at night, and lose a few grains of rock each year to the infrequent Egyptian rains. They have lasted 4,500 years so far,3 but one day they will all weather away to mere lumps.
We humans mentally divide up the world for ourselves: things that are perishable and those that are permanent; things we expect to replace and those we take for granted; problems we should try to solve and situations we should accept and, perhaps, merely strive to hold our own. But those mental cubbyholes are really just placeholders along the spectrum of a vast and slippery existence. We expect the car we drive to wear out and not be worth fixing after a couple of hundred thousand miles, if not sooner. We don’t expect grandma’s dining room table ever to wear out and need replacing—unless we find it too big for our current apartment or too antique for our modern lifestyle. And we want to believe that the garage structure where we park our fragile cars will last forever.
But existence is a process, trending from one state to another, and not one subject to root cause analysis and resolution. One day, even our Sun will burn out, and that will not be a design defect but a simple fact of existence.
1. “Six sigmas” is a reference in statistics to a degree of accuracy or consistency, in which a production run is defect-free or a process performs accurately 99.999% of the time. Technically, the term represents six standard deviations between the process mean and the nearest specification limit—and if I could explain that to you in English, I’d be an engineer. The initial practice of Six Sigma techniques originated at Motorola in the 1960s, was picked up by Jack Welch at General Electric, and has since become a standard in many industries to reduce process variation, increase process efficiency, and improve overall product quality. People take formal training in these techniques by proposing and completing improvement projects and are awarded with metaphorical green and black belts, much like a martial art.
2. And once, long ago, cars regularly needed new sparkplugs and contact points in their ignition systems, while bicycles and motorcycles needed new drive chains. Improving technology has gradually redesigned, toughened, or eliminated many of these fragile components until the replacement cycle is beyond the casual awareness of the general public.
3. The pyramids once were sheathed in a smooth layer of white limestone, creating a brilliant, reflecting surface. An earthquake in the 14th century loosened these casing stones, and the locals carted them away to build Cairo. That left the blocky, stepped appearance we know today.