The Software Maturity Index (SMI) is defined as $SMI=[M_f – (F_a +F_c + F_d)] / M_f$
where $M_f$= number of modules in current release
$F_a$ =the number of module in the current release that have been added
$F_c$ = the number of module in the current release that have been changed
$F_d$= the number of module in the current release that have been deleted
The product begins to stabilize when
- SMI approaches 1
- SMI approaches 0
- SMI approaches -1
- None of the above