Defect Detection Efficiency

Software Testing Methods
Software Quality



Defect Detection Efficiency (DDE) is the number of defects detected during a phase/stage that are injected during that same phase divided by the total number of defects injected during that phase.


  • defects:
    • Are confirmed and agreed upon (not just reported).
    • Dropped defects are not counted.
  • phase:
    • Can be any phase in the software development life cycle where defects can be injected AND detected. For example, Requirement, Design, and Coding.
  • injected:
    • The phase a defect is ‘injected’ in is identified by analyzing the defects [For instance, a defect can be detected in System Testing phase but the cause of the defect can be due to wrong design. Hence, the injected phase for that defect is Design phase.]


  • DDE = (Number of Defects Injected AND Detected in a Phase / Total Number of Defects Injected in that Phase) x 100 %

Defect Detection Efficiency Image


  • Percentage (%)


  • The ultimate target value for Defect Detection Efficiency is 100% which means that all defects injected during a phase are detected during that same phase and none are transmitted to subsequent phases. [Note: the cost of fixing a defect at a later phase is higher.]


  • For measuring the quality of the processes (process efficiency) within software development life cycle; by evaluating the degree to which defects introduced during that phase/stage are eliminated before they are transmitted into subsequent phases/stages.
  • For identifying the phases in the software development life cycle that are the weakest in terms of quality control and for focusing on them.


Phase Injected Defects Injected Phase Specific Activity Detected Defects Detected Phase Specific Activity Detected Defects that were Injected in the same Phase Defect Detection Efficiency
Require- ments 10 Require- ment Develop- ment 4 Require- ment Review 4 40.00%[= 4 / 10]
Design 24 Design 16 Design Review 15 62.50%[= 15 / 24]
Coding 155 Coding 23 Code Review 22 14.19%[= 22 / 155]
Unit Testing 0 25 Unit Testing
Integra- tion Testing 0 30 System Testing
System Testing 0 83 Integration Testing
Accept- ance Testing 0 5 Acceptance Testing
Opera- tion 0 3 Operation
  • The DDE of Requirements Phase is 40.00% which can definitely be bettered. Requirement Review can be strengthened.
  • The DDR of Design Phase is 62.50 % which is relatively good but can be bettered.
  • The DDE of Coding Phase is only 14.19% which can be bettered. The DDE for this phase is usually low because most defects get injected during this phase but one should definitely aim higher by strengthening Code Review. [Note: sometimes, Coding and Unit Testing phases are combined.]
  • The other Phases like Integration Testing etc do not have DDE because defects do not get Injected during these phases.
Software Testing Methods
Software Quality