Modeling Software Defect Dynamics

At USC-CSSE we were evaluating and updating software
cost and quality models for critical NASA flight projects [3].
A major focus of the work was to assess and optimize quality
processes to minimize operational flight risks. We extended
the COQUALMO model for software defect types classified
with ODC. ODC COQUALMO decomposes the top-level
defect types into more granular ODC categories.

The ODC taxonomy provides well-defined criteria for
the defect types and has been successfully applied on NASA
projects. The ODC defects are then mapped to operational
flight risks, allowing “what-if ” experimentation to determine
the impact of techniques on specific risks and overall flight risk.
The tool was calibrated to ODC defect distribution patterns
per JPL studies on unmanned missions. A Delphi survey was
completed to quantify ODC defect detection efficiencies,
gauging the effect of different defect removal techniques against
the ODC categories.