Purchasing behaviour and supplier base evolution – a longitudinal case study

The purpose of the paper is to describe and analyse the evolution of the supplier base of a buying firm and the reasons behind these changes.

The paper is based on a case study of the changes over 52 years in a sub-set of the supplier base of a firm manufacturing fork-lifts.

The study shows that some relationships feature substantial longevity. However, the duration of one-third of the total relationships is shorter than five years. There was considerable variation over time in the dynamics of the supplier base in terms of entries and exits of suppliers. Owing to this variation, research findings and conclusions in short-term studies are heavily dependent on the specific conditions at the time of the study. Finally, no less than one-fourth of the terminated supplier relationships were reactivated later.

The study was designed in a time when purchasing was considered entirely from the perspective of the buying firm. Further studies, therefore, must increasingly emphasise the role of suppliers and the interaction in the buyer–supplier relationships, as well as the embeddedness in networks.

The findings of the study are unique in two ways. First, they are based on systematic observations over more than 50 years. Second, the study involves the purchases of 11 components representing different technical and economic features. The (few) previous studies are based on much shorter time periods and involves fewer suppliers/components. Moreover, the findings regarding re-activation of terminated relationships represent unique contributions.