BUSINESS PROCESS MODELING - FROM INFORMAL TO FORMAL PROCESS REPRESENTATIONS - Petra Elgass, Helmut Krcmar Universität Hohenheim Lehrstuhl für Wirtschaftsinformatik D 70593 Stuttgart Germany Andreas Oberweis Universität Karlsruhe Institut für Angewandte Informatik und Formale Beschreibungsverfahren D 76128 Karlsruhe Germany Abstract In this paper we propose a concept for the stepwise development of formal business process models, starting from a semi-formal process model represented by customer/supplier-relationship diagrams. These diagrams focus on communication features of business processes and stress aspects like customers' requirements and satisfaction. They are especially useful at the early stages of process modeling, when the process is to be structured. The formal process model on the other hand is based on high-level Petri nets, which allow an integrated, procedural description of object and behaviour related aspects. Additionally, business rules can be declaratively expressed in Petri nets. The formal process model is directly executable. It can be evaluated by means of simulation and formal analysis and can also serve as basis for later implementation. 1. Introduction and Motivation Continuous transformations of the world market system, competitive pressure, shorter product life cycles, increasing customer demands as well as dramatic technological progress are affecting businesses during the 1990s. These factors require a stronger market and customer orientation of the enterprises. The restructuring of the enterprises' organization with respect to the core business processes and the innovation or reengineering of business processes [2, 8] are proposed as the key to success. However, some studies [7] show that disproportionally many projects aiming at