The Effects of Variability in Demand and Time Parameters for Multi-Item, Multi-Echelon, Multiindenture Reparable Inventory Systems

This research sought to describe an alternative way for calculating expected back order (EBO) for reparable inventory systems. The high costs associated with reparable items management, together with its importance for system's availability, make the assessment of back orders of great importance in supporting decisions of what-to-buy and where-to- locate those items. Starting at the point that existing models (METRIC, MOD-METRIC, and VARIMETRIC) rely on some assumptions that often cannot be met in real life, the proposed method (called P-METRIC), which is a mix of simulation and mathematical analytical model, relaxes assumptions about Demand, Time to Repair (TTR), and Ordering and Ship Time (OST) distributions looking for potential differences that may cause on the EBO calculation. The study consists of 10 conceptual examples where the parameters of Demand, TTR, and OST vary according to probability distributions recognized by the related literature.