A practical classification rule for a SQ (software quality) model considers
the needs of the project to use a model to guide targeting software RE (re
liability enhancement) efforts, such as extra reviews early in development.
Such a rule is often more useful than alternative rules. This paper discus
ses several classification rules for SQ models, and recommends a generalize
d classification rule, where the effectiveness and efficiency of the model
for sliding software RE efforts can be explicitly considered. This is the f
irst application of this rule to SQ modeling that we know of,
Two case studies illustrate application of the generalized classification r
ule.
A telecommunication-system case-study models membership in the class of fau
lt-prone modules as a function of the number of interfaces to other modules
.
A military-system case-study models membership in the class of fault-prone
modules as a function of a Set of process metrics that depict the developme
nt history of a module.
These case studies are examples where balanced misclassification rates resu
lted in more useful and practical SQ models than other classification rules
.