Software Quality Metrics

Attribute	Description	Metrics /Measure
Correctness	The degree to which the software performs the required functions accurately	Defects / KLOC or Defects / Function points
Maintainability	Maintainability is the ease with which a program can be correct if an error occurs.	MTTC (Mean time to change) -- Once error is found, how much time it takes to fix it in production.
Integrity	This measure the system’s ability to with stand attacks to its security	Integrity = Summation [(1 - threat) X (1 - security)]
Usability	How usable is your Software program	* -Skill required to learn the system * -Time required to be productive on new system * -Net increase in productivity by use of the new system. * User questionnaire survey results
Defect Removal Efficiency	Defect Removal Efficiency (DRE) is a measure of the efficacy of your SQA activities..Ideal value of DRE should be 1 which means no defects found.	DRE = E / ( E + D ) Where E = No. of Errors found before delivery of the software and D = No. of Errors found after delivery of the software.
Test Coverage		Number of units (KLOC/FP) tested / total size of the system
Quality of Testing =		No. of defects found during Testing/(No. of defects found during testing + No of acceptance defects found after delivery) *100
Customer satisfaction index		Number of system enhancement/Maintainence requests per year Call volume to customer service hotline
Reliability		Availability (percentage of time a system is available, versus the time the system is needed to be available) - Mean time between failure (MTBF) - Mean time to repair (MTTR) - Reliability ratio (MTBF / MTTR) - Number of product recalls or fix releases - Number of production re-runs as a ratio of production runs