Root cause analysis (RCA) is a method of error analysis that involves retrospective investigations. Error analysis, using a different conceptual strategy, may also involve prospective attempts to predict error modes.
One of the most commonly used perspective approaches is failure mode and effect analysis (FMEA). RCA is used primarily to examine the underlying contributors to an adverse event or condition. FMEA differs in that its primary use is to evaluate a process prior to its implementation. Its purpose is to identify ways in which a process might possibly fail, with the goal being to eliminate or reduce the likelihood of such a failure.
In the FMEA, a process flowchart is used and a team performs the following tasks:
- Each process is listed.
- Brainstorming of potential points of failure is documented.
- The potential effects of each failure are discussed and severity rankings are assigned.
- Occurrence (frequency) and detection (chances the failure will be discovered prior to occurrence) are ranked.
- Calculations are made using these rankings.
- An action plan follows, whereby failures will be worked out.
- Action is taken (where improvements are then implemented)
- Re-evaluation of the processes and potential failures takes place.
