Root Cause Analysis (RCA) is a methodology for problem solving and process improvement.
A root cause is simply that; the ‘root’ to a problem.
Root Cause Analysis (RCA) is a set of techniques to help identify the root cause of a problem. The need for RCA comes from the fact that the elimination of the symptoms of the problems is not alone sufficient to address the problem, it has to be addressed at the cause level. If you solve a problem at this root level, it is highly probable that you can prevent its recurrence.
Although identifying root causes forms the most important aspect of solving the problem, these causes are only secondary to the solutions sought to prevent such recurrence in the future.
A little history…
RCA is generally credited to the founder of Toyota Industries Co., Ltd., Sakichi Toyoda. The technique Toyoda developed for identifying root causes to problems was called the “5 Whys’’. Basically, keep asking why something happened, about five times, and the main cause of the problem will be revealed. Simple and highly effective.
Although this system was praised within Toyota, it was later criticized by Teruyuki Minoura, the Managing Director of global purchasing for Toyota, for its potential bias across different employees asking new sets of “whys" each time, based on their own experiences and depth of knowledge. There was also no method of knowing if the questions asked were the correct questions to be asked in the first place. No systematic approach nor standardised techniques I here you shout!
RCA has evolved over time to address these concerns with different approaches to help investigators identify the most probable root cause to eliminate. One of the most globally successful collection of tools to investigate root cause and reduce defects is Six Sigma, a technique pioneered by Motorola in 1986 and then further developed by General Electric (GE) into the more recognised standard we see today.
This RCA Pocket Guide is a simple 5 step approach to help QC professionals identify the root cause of a problem and identify solutions to prevent recurrence.