Statistical Process Control is a great tool. Reducing variability on any
process seems at first glance to be a "good thing" (with apologies to Martha S).
But when you apply it with focus it can turn into pure gold.
Theory of Constraints is the focusing technology that can tell you - with
pin-point precision - where a process improvement merely looks good; and where
it will translate directly into a bottom line improvement. Return on Investment
becomes highly predictable; and SPC's perceived value is amplified. Check the
TOC out.