Discovering Patterns for Inter-Organizational Business Collaboration in a Top-Down Way A. Norta and P. Grefen Eindhoven University of Technology, Faculty of Technology and Management, Department of Information Systems, P.O. Box 513, NL-5600 MB, Eindhoven, The Netherlands. a.norta@tm.tue.nl Abstract. In the area of business-to-business (B2B) collaboration, original equip- ment manufacturers (OEMs) are confronted with the problem of spending a con- siderable time and effort on coordinating suppliers across multiple tiers of their supply chain. In tightly integrated supply chains the failure of providing services and goods on time leads to interruptions of the overall production and subse- quently results in customer dissatisfaction. This paper proposes the concept of electronic Sourcing as a new approach for improving the coordination of service provision across several tiers of a supply chain. Sourcing allows for the harmo- nization of heterogenous system environments of collaborating parties without requiring a total disclosure of internal business details to the counterpart. Fur- thermore, with tool support in Sourcing it is possible to verify the correct ter- mination of processes and the contractual adherence of service provision with- out imposing fixed standardized routing. As Sourcing is a new proposal for B2B supply-chain collaboration, this paper analyses features of the Sourcing concept in a pattern-based way. However, differently to intra-organizational perspectives such as control-flow, data-flow, or resource, where established in-house workflow systems and web service composition languages (WSCLs) were analyzed for pat- terns, this paper pursues an analysis of Sourcing patterns in a top-down way. The reason for proceeding top-down is a lack of available systems for B2B collabo- ration that have gone through a lengthy period of adoption to real world business activities. The discovered and specified Sourcing patterns of this paper are instru- mental in the EU-FP6 project CrossWork for the conduction of case studies with industry partners from the automobile industry. 1 Introduction After exploring and successfully applying workflow concepts for intra-organizational applications [6, 31], enterprizes in the B2B domain are faced with the next challenge of achieving increased efficiency and effectiveness in the area of inter-organizational col- laboration for commercial exchanges. Traditionally, a business transaction starts with negotiating and defining a contract that contains essential elements like the clear spec- ification of a service that needs to be provided by one contracting party and how much compensation is offered by another contracting party that consumes this service. The parties involved in the contract have their own internal processes that need to be aligned inter-organizationally for the duration of the enactment of a business transaction. How- ever, collaborating companies are confronted with many problems. For example, the