This research investigates why certain Enterprise-Resource Planning (ERP) system adopters pursue different levels of customization of the software in the course of their implementation, in spite of the generally accepted best-practice heuristic of limited customization. We have collected qualitative data through semi-structured interviews with key implementation managers in ERP adoption projects and consulting firms specializing in ERP implementations. The study develops a theoretical model of customization drivers, explaining their relationship to system customization. The model suggests that high customization may occur because of unnecessary redevelopment of functionality that is available in the ERP system standard, resistance to change based on low project acceptance and cultural issues, insufficient weight of the implementation team’s recommendations, consultants’ acceptance of the organization’s wish to customize the system, and because of the classification of too many business processes as unchangeable. The results of the study also explain how these problems occur and why they lead to high system customization.
