Mult-Echelon Models

The Navy currently uses inventory models which determine the optimal inventory policy for each activity or echelon of supply independently of the other supply activities. In addition, the Navy uses supply effectiveness measures which are requisition oriented rather than readiness oriented. Many inventory models, known as multi-echelon models, have been developed which feature both a readiness performance measure and multi-echelon supply modeling. The multi-echelon models which have been proposed for use or are currently being used by the military services have at least one of three purposes: (1) to tie budget dollars to readiness, (2) to determine the inventory levels required at each echelon of supply given a readiness objective, or (3) to predict readiness given the inventory levels at each echelon of supply. Therefore, the model which is best for the Navy will depend on the Navy's intended use of the model. This study examines and contrasts the characteristics of the multi-echelon models currently used or proposed for use in the military services, in order to choose models which may fit the Navy's needs.