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. By directing corrective measures at root causes, it is hoped that the likelihood of problem recurrence will be minimized. However, it is recognized that complete prevention of recurrence by a single intervention is not always possible. Thus, RCA is often considered to be an iterative process, and is frequently viewed as a tool of continuous improvement.

Root cause analysis is not a single, sharply-defined methodology; there are many different tools, processes, and philosophies of RCA in existence. However, most of these can be classed into four, very-broadly defined "schools" that are named here by their basic fields of origin: safety-based, production-based, process-based, and systems-based.

• Safety-based RCA descends from the fields of accident investigation and occupational safety and health. Root causes tend to be viewed as failed or missing safety barriers, unrecognized risks or hazards, or inadequate safety engineering.
• Production-based RCA has its origins in the field of quality control for industrial manufacturing. This school of RCA tends to view a root cause as the original cause of a non-conformance, which is consistent with the notion of a production line consisting of many sequential steps, one or more of which may be malfunctioning or out of tolerance.
• Process-based RCA is basically a follow-on to production-based RCA, but with a scope that has been expanded to include business processes outside of manufacturing. The basic view of a root cause in this school is that individual process failures are the source of problems. This type of RCA is closely allied with the practice of process improvement.
• Systems-based RCA has emerged as an amalgamation of the preceding schools, along with ideas taken from fields such as change management, risk management, and systems thinking. A root cause, according to this school, often exists at the level of organizational culture and strategic management.

Despite the seeming disparity in purpose and definition among the various schools of root cause analysis, there are some general principles that could be considered as universal. Similarly, it is possible to define a general process for performing RCA.

General 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.

General process for performing root cause analysis

1. Define the problem.
2. Gather data/evidence.
3. Identify problems that contributed to problem (Causal Factors).
4. Find root causes for each Causal Factor.
5. Develop solution recommendations.
6. Implement the solutions.

External links

• Noordwijk Risk Initiative Foundation
• Root Cause Analysis Articles
• Root Cause Live
• REASON Root Cause Analysis
• RealityCharting™ Root Cause Analysis - Apollo's Root Cause Analysis Software

Quality | Evaluation methods