Even so, we must recognize that a sale lost today is a sale lost forever. Installing a
JIT system so that it operates with very little interruption is not a short-run project.
Thus, losing sales is a real cost of installing a JIT system. An alternative, and perhaps
complementary approach, is the theory of constraints (TOC). In principle, TOC can
be used in conjunction with JIT manufacturing. After all, JIT manufacturing environments
also have constraints. Furthermore, the TOC approach has the very appealing
quality of protecting current sales while also striving to increase future sales by increasing
quality, lowering response time, and decreasing operating costs. However, before we
introduce and discuss the theory of constraints, we need to provide a brief introduction
to constrained optimization theory