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 prospective approaches is failure mode and effect analysis or FMEA. Root cause analysis 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 (i.e, reduce risk).