Root Cause Analysis (RCA) is a class of problem solving methods aimed at identifying the root causes of problems or events.

The practice of RCA is predicated on the belief that problems are best solved by attempting to correct or eliminate root causes, as opposed to merely addressing the immediately obvious symptoms.

Principles of Root Cause Analysis

1. Aiming corrective measures at root causes is more effective than merely treating the symptoms of a problem.
2. To be effective, RCA must be performed systematically, and conclusions must be backed up by evidence.
3. There is usually more than one root cause for any given problem.

Process of Performing Root Cause Analysis

1. Define the problem.
2. Gather data/evidence.
3. Identify issues that contributed to the problem.
4. Find root causes.
5. Develop solution recommendations.
6. Implement the recommendations.
7. Observe the recommended solutions to ensure effectiveness

Root Cause Analysis Techniques

1. 5 Whys
2. Failure mode and effects analysis
3. Pareto analysis
4. Fault tree analysis
5. Bayesian inference
6. Ishikawa diagram, also known as the fishbone diagram or cause and effect diagram
7. Barrier analysis - a technique often used in particularly in process industries. It is based on tracing energy flows, with a focus on barriers to those flows, to identify how and why the barriers did not prevent the energy flows from causing harm.
8. Change analysis - an investigation technique often used for problems or accidents. It is based on comparing a situation that does not exhibit the problem to one that does, in order to identify the changes or differences that might explain why the problem occurred.
9. Causal factor tree analysis - a technique based on displaying causal factors in a tree-structure such that cause-effect dependencies are clearly identified.