Portfolio models have been used in strategic planning and marketing, but th
eir application to the field of purchasing has been limited. This seems, ho
wever, to be changing, as procurement management has become more strategic.
Applying portfolio models to purchasing can introduce a major risk in that
the implications for suppliers and/or operational staff are scarcely consi
dered. This article explores existing portfolio models in purchasing, which
classify purchases into different product categories. Based on case studie
s of two automotive OEMs and two vehicle industry suppliers (all European),
together with benchmarking interviews at Toyota, Japan, we attempt, firstl
y, to link these product categories to different types of suppliers and, se
condly, to link the product categories and the supplier types to the specif
ication process-in other words, to link the specification types and the spe
cification generators. We argue that product categories must be matched by
distinctive suppliers that have the required capabilities and capacities to
satisfy specific product demands. The connection between the portfolio mod
els and the specification process will help original equipment manufacturer
s (OEMs) and suppliers to improve relations with each other. (C) 2000 Elsev
ier Science Ltd. All rights reserved.