Date of Award


Document Type


Degree Name

Master of Science


Department of Operational Sciences

First Advisor

John O. Miller, PhD


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 & 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. It also presents a case study of 20 reparable items of the T-27 Tucano, an advanced-training, light-attack deployed by the Brazilian Air Force. EBO numbers of the existing and proposed models are compared with results gathered from simulation (conceptual examples) and a field research (T-27 Tucano) in order to allow conclusions about the accuracy and suitability of the proposed method.

AFIT Designator


DTIC Accession Number