Introduction

Robert Nelms' has said that Root Cause Analysis (RCA) begins by examining catastrophic events, but ends up looking at the small things that cause the big ones. This lends credibility to the need to get the basics right first. It's the confluence of many little things done poorly that usually results in some big, bad thing happening. And, according to William Salot, RCA is any evidence-driven process that, at a minimum, uncovers underlying truths about past adverse events, thereby exposing opportunities for making lasting improvements. Let's explore this further.

There are many reasons why problems occur. For each reason, there are often many underlying reasons why the original event happened, and indeed in many cases a complex event tree can be created that describes at each level the additional underlying reasons for the previous event. As Nelms observed, catastrophic events more often than not result from the confluence of a number of small actions that ultimately led to the catastrophe. If any one of the actions that were a contributor to the confluence of circumstances had been eliminated earlier, the catastrophic incident would not have occurred. Fortunately this complexity minimizes the risk of major accidents or incidents. Unfortunately, it makes them more difficult to prevent, since any one event may seem innocuous or unimportant. RCA is a way of identifying root causes so that action can be taken to prevent them...