Every event is result of causal chain, in that something has happened because on something else has occurred. Its often important to understand why something has happened in order to mitigate the negative effects and prevent it from happening again.

Root cause analysis (RCA) is the process of discovering the root cause of the problem in order to identify the appropriate solution.

Cause and effect diagram, most commonly know as fishbone diagram is the simplistic and effective way of identifying the root cause of the defects. The diagram is also referred as Ishikawa diagram, Herringbone diagram or Fishikawa (Fish diagram created by Kaoru Ishikawa)