How do we define service in a multiechelon situation? Normally, service is measured only at the lowest echelon. In a multiechelon system, a stockout at one of the higher echelons has only a secondary effect on service: it may lengthen the lead time for a lower echelon, which ultimately may cause customer disservice. We can see that safety stock at a particular echelon has effects on stockouts at other echelons. Thus, we have to be careful to avoid unnecessary duplication of safety stocks.? P-96