The research has tried to understand why using the same information system development method, one can be led to success or failure. The study has been grounded on practical investigations in different organizations. The observations are confronted with three theories, found in the literature, which have proposed contingency factors, related to the project or its context. According to the authors, the right method to be selected and the way of implementing have to fit with those factors. The research has showed that there are in fact three processes, which have to be managed in a consistent way: production, decision and change. Methods usually focus on the production process, whereas implementing successfully a method on a project implies to control simultaneously decision taking, attitude changes and production activities. It is precisely this control which requires to be fitted with the characteristics of the project
