One has to decide on
the trade-o between these factors.
Traditionally this has been done by using WIP
inventory holding costs and lost order costs.
However, in practice, both of these costs, es-
pecially the lost order costs, are very hard to
de®ne. Therefore, in this paper, the analytic
hierarchy process (AHP) is presented in order
to present experts with a set of choices so that
they can decide on the trade-o