DEFECT DETECTION EFFICIENCY Fundamentals
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.
- Are confirmed and agreed upon (not just reported).
- Dropped defects are not counted.
- Can be any phase in the software development life cycle where defects can be injected AND detected. For example, Requirement, Design, and Coding.
- 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 %
- 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||—||—|
- 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.