Defect Density

Defect Density

Defect Density Definition
Defect Density is the number of confirmed defects detected in software/component during a defined period of development/operation divided by the size of the software/component.

Elaboration
The 'defects' are:

confirmed and agreed upon (not just reported).
Dropped defects are not counted.

The ‘period’ might be for one of the following:

for a duration (say, the first month, the quarter, or the year).
for each phase of the software life cycle.
for the whole of the software life cycle.
The ‘size’ is measured in one of the following:

Function Points (FP)
Source Lines of Code


Defect Density Formula


Defect Density Uses
For comparing the relative number of defects in various software components so that high-risk components can be identified and resources focused towards them
For comparing software/products so that ‘quality’ of each software/product can be quantified and resources focused towards those with low quality.