approaches among the various schools of root cause analysis and the specifics of each application domain, RCA generally follows the same four steps: Identification and description: Effective problem statements and event descriptions (as failures, for example) are helpful and usually required to ensure the execution of appropriate root cause analyses. Chronology: RCA should establish a sequence of events or timeline for understanding the relationships between contributory (causal) factors, the root cause, and the problem under investigation. Differentiation: By correlating this sequence of events with the nature, the magnitude, the location, and the timing of the problem, and possibly also with a library of previously analyzed problems, RCA should enable the investigator(s) to distinguish between the root cause, causal factors, and non-causal factors. One way to trace down root causes consists in using hierarchical clustering and data-mining solutions (such as graph-theory-based data mining). Another consists in comparing the situation under investigation with past situations stored in case libraries, using case-based reasoning tools. Causal graphing: Finally, the investigator should be able to extract from the sequences of events a subsequence of key events that explain the problem, and convert it into a causal graph. To be effective, root cause analysis must be performed systematically. The process enables the chance to not miss any other important details. A team effort is typically required, and ideally all persons involved should arrive at the same conclusion. In aircraft accident analyses, for example, the conclusions of the investigation and the root causes that are identified must be backed up by documented evidence. Transition to corrective actions The goal of RCA is to identify the root cause of the problem with the intent to stop the problem from recurring or worsening. The next step is to trigger long-term corrective actions to address the root cause identified during RCA, and make sure that the problem does not resurface. Correcting a problem is not formally part of RCA, however; these are different steps in a problem-solving process known as fault management in IT and telecommunications, repair in engineering, remediation in aviation, environmental remediation in ecology, therapy in medicine, etc. Challenges Without delving in the idiosyncrasies of specific problems, several general conditions can make RCA more difficult than it may appear at first sight. First, important information is often missing because it is generally not possible, in practice, to monitor everything and store all monitoring data for a long time.