Root cause – what it is and why it’s important

The term root cause is used in engineering and related disciplines. It simply means identifying the source of a bigger issue. Finding the root cause helps to keep the problem from happening again.

What is root cause analysis?

root cause
In any system, all the components are related, even if only indirectly. To find root cause, you have to consider all parts of the system, not just the one where you identified the issue. The root cause could lie elsewhere.

I worked briefly as a government consultant for a small engineering firm. Any time something went wrong, we created a root cause analysis. The document listed what went wrong, what we learned, and identified the source of the issue. We then made recommendations to keep the problem from happening again.

It was generally effective. I participated in root cause analyses for everything from someone discovering a user account that had too many rights to Microsoft Word documents not formatting correctly. Our recommendation in the first case was to perform an audit to ensure all user accounts were provisioned quickly. Our recommendation in the second was to make sure everyone had the same version of Microsoft Office and the same fonts installed.

Later in my career, I worked at a software vendor. Our largest customers wanted a root cause analysis when something major went wrong. We wrote the analysis, made the changes, and provided them a copy. The root cause in this case could vary. Sometimes it was a bug in a new feature. Sometimes it was hardware failure.

Creating a root cause analysis is always a good thing, as it’s a learning experience. Providing it to large customers? I have mixed feelings. It can turn into punishment, rather than quality assurance. If it’s about quality assurance and accountability, occasionally providing a lightly redacted copy can be a good thing. It’s best to try not to make it about penance.

Analyzing root cause in my own home

Let’s take an example of a problem and chase down root cause. This is something anyone can relate to. One Saturday morning, my wife told me the dishwasher wouldn’t drain.

I bailed out the water, and I found a few problems. I found a bit of plastic that shouldn’t be there. I also found two fouled filters. So I cleaned out the filters, including a lot of grease on one. Then I carefully put everything back together… and the dishwasher still wouldn’t drain.

Finally I thought to ask when she first noticed the problem. She couldn’t remember. But it had worked prior to Tuesday. I couldn’t speak for Wednesday, Thursday, or Friday because I’d been out of town. But before I’d left, I replaced our garbage disposal. Now you either know the answer, or you’re super-confused. Stay with me for a minute if you’re confused.

I turned to the garbage disposal. Garbage disposals have a plug you have to remove so the dishwasher can drain into them. I couldn’t remember whether I’d removed that plug. At this point, the most reasonable explanation was that I’d forgotten to remove the plug, and that was why my dishwasher stopped draining.

I unplugged the disposal, removed the hose, poked around with a screwdriver, and hit something solid about an inch and a half in. The plug was still there. I removed the plug, put everything back together, and my dishwasher came back to life.

My root cause was not removing the plug when I installed the garbage disposal. It wasn’t the only problem, and fixing those filters sure made my dishwasher work better afterward. But the plug was the biggest issue.

And the lesson learned is to make sure I remove that plug the next time I change a disposal.

Why this practice matters

The reason to do root cause analysis is to ensure problems don’t happen again. Preventing problems is usually cheaper than fixing them. So if you can identify the root cause and fix it, the problem doesn’t occur.

And like my dishwasher example, frequently the root cause can be something that appears unrelated. I didn’t touch my dishwasher, but changing something downstream of the dishwasher broke the dishwasher.

You can use the same methodology on other things too, like business or social issues. Why did Crestwood Plaza close? Crestwood Plaza was once the heart of a booming commercial district. The obvious reason for its demise was a neighboring city, Sunset Hills, building a modern open-air shopping center less than two miles away. But that plan fell through, the center never got built, and Crestwood Plaza went under anyway.

I think the root cause was the shifting population in the St. Louis area. Crestwood is an inner-ring suburb. For years, people avoided the outer ring areas of St. Louis County. Some cities were industrial, like Fenton. Other areas were just hard to reach and no one lived there. But over time, those sparsely populated areas grew. Thousands of new homes sprung up in Fenton in the late 1980s. At first this was good for Crestwood, because the new Fenton residents shopped there. But over the first decade of the 21st century, Fenton’s commercial district grew. By 2010, if anything, Crestwood residents were shopping in Fenton rather than the other way around.

So while the failed development in Sunset Hills accelerated the demise of Crestwood Plaza, I think the root cause was the growth of Fenton.

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