• Defects should be categorized or classified into class and subclass for effective root cause analysis
  • Once we group a set of defects in to defect class and subclass, root cause(s) for these class and subclass can be identified
  • It also possible to re-use the process artifacts /reuse the knowledge from past root cause analysis
  • Each defect is symptom of one or more cause and it is these cause that have to be analyzed so that we can prevent defects from occurring repeatedly
  • Also the phase injected and detected should be classified appropriately