Many times, when a problem happens, actions are taken to fix it without knowing what the problem is. To avoid that, PDCA gives a structure for the problem-solving process.
Understanding the problem is critical for the success of PDCA, and knowing the root cause is an important piece. Without identifying the underlying cause, it is impossible to implement corrective actions that prevent a recurrence. If all we need to stop a problem from repeating itself is find the root cause, why we keep fighting with the same situations?
Root cause analysis (RCA) is one of those things that is easier said than done. While it is not complicated, finding the root cause requires patience, attention to detail, and the ability to look at things from different perspectives. RCA is a structured process for identifying the most basic causal factor(s) that if corrected or removed will prevent recurrence of an undesired outcome.
It is common to engage in finding a solution when the situation is almost out of control. At this point, patience is out of the picture you want to see fast results. RCA requires persistence to keep asking why that happens until finding the end cause. If you stop digging before finding the most basic cause, the process fails. You end up working with the physical cause, which is a symptom or a proximate cause.
A proximate or physical cause is the source of the symptoms that you see as the problem. Recommendations to fix this type of cause are corrective actions, but they do not prevent a recurrence.
To have different points of view of the situation, brainstorm ideas with the affected members of the team. Create a blame-free, safe environment where people can talk honestly. Encourage thinking out of the box, and asking why to find buried reasons.
Root causes are specific basic causes that management has control to fix and develop effective recommendations to avoid recurrence. For example, human error is not specific. Why the person errs? There is another uncover reason like, Is the work instruction clear? Is it complete? Is there any distraction that affects performance? An example of something you cannot control is the weather. Because you cannot control the weather, it is necessary to keep digging what reason is hiding behind weather conditions.
The goal of RCA is to identify one or two reasons, that, if corrected will reduce recurrence. Tools like fishbone or the 5 Why facilitate this process. The rule of thumb is that if there are three or more root causes, you can assume the root cause has not yet been found, and you need additional investigation. In summary, keep digging!