* Corresponding author. Tel.: #31-346-581681; fax: #31- 346-581699. E-mail address: janw.rustenburg@districon.nl (W.D. Rustenburg). Int. J. Production Economics 71 (2001) 177}193 Spare parts management at complex technology-based organizations: An agenda for research W.D. Rustenburg*, G.J. van Houtum, W.H.M. Zijm Districon Logistics Management Consultants, P.O. Box 188, 3600 AD Maarssen, Netherlands Eindhoven University of Technology, Netherlands Abstract This paper explores the applicability of sophisticated models and techniques for spare parts inventory management within a highly technology-driven environment, viz. the Royal Netherlands Navy. In particular, we discuss the structure of the so-called VARI-METRIC models, a set of tools that has been designed for decision support in spare parts management, initially in a military organization. These tools aim at a high availability of complete technical systems, as opposed to more classical inventory management approaches, that are primarily directed towards a high availability of individual items. Unfortunately, the VARI-METRIC models su!er from a series of limiting assumptions that are not satis"ed in most technology-based large organizations. We identify these shortcomings and suggest a research agenda to deal with these issues. Important extensions include the study of capacitated systems, and the study of hybrid product structures, consisting of both repairable and consumable parts. When consumption and condemnation occur (i.e. not every broken part can be repaired), the operational availability of systems during their exploitation period becomes a function of the allocated resupply budgets. This highly important "eld, relating issues such as maintenance policies, spare parts repair and resupply, to concepts of life cycle management, seems unexplored so far.  2001 Elsevier Science B.V. All rights reserved. Keywords: Inventory management; Multi-echelon systems; Indenture levels; (Re)Supply budgets 1. Introduction During the last decades, as a result of a changing political landscape as well as changes in the public opinion, many military organizations have been confronted with seriously declining budgets. Tight budget constraints may lead either to a disposal of tasks, or to e!orts to increase the overall e$ciency and quality of the work, to improve the responsive- ness to the often internal customers, while at the same time a leaner organization is pursued (do more with less). Many projects have been started to implement state-of-the-art Information Techno- logy (IT) tools, to streamline the organization (less hierarchical levels, introduction of autonomous work teams) and to restructure both production and materials management. An example of such an adaptation of a military organization towards rapidly changing circumstan- ces is constituted by a number of business re- engineering projects carried out at the Royal Netherlands Navy (RNLN). Earlier work on the organizational changes as well as the design of 0925-5273/01/$-see front matter  2001 Elsevier Science B.V. All rights reserved. PII:S0925-5273(00)00117-1