Service level analysis of (S - 1, S) inventory policy for negative binomial distributed failures

This paper deals with the analysis of uncertain parameters in the (S - 1, S) inventory control policy. In order to determine the number of spare parts under the policy, parameters in a probability model for the number of failures during a replenishment lead time should be interpreted first. In case of the negative binomial distributed failures, the presented interpretation facilitates the incorporation of experts' opinions into the estimation of uncertain parameters. Determination of parameters via their interpretation is useful for deciding a service level in the area of reliability-based inventory control.