Root Cause Analysis
Root cause analysis (RCA) is a method of problem solving that tries to identify the root causes of faults or problems.
RCA practice tries to solve problems by attempting to identify and correct the root causes of events, as opposed to simply addressing their symptoms. Focusing correction on root causes has the goal of preventing problem recurrence. RCFA (Root Cause Failure Analysis) recognizes that complete prevention of recurrence by one corrective action is not always possible.
http://en.wikipedia.org/wiki/Root_cause_analysis