Event-driven process chain

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Simple example

The event-controlled process chain ( EPC ) is a graphic modeling language for the representation of business processes in an organization in business process modeling / representation of the process organization (processes and work steps) in company mapping . It was developed in 1992 by a working group led by August-Wilhelm Scheer at the Saarland University in Saarbrücken as part of a research project with SAP SE for the semi-formal description of business processes. The method was developed within the framework of the architecture of integrated information systems (ARIS) for the view-oriented modeling of business processes and is an essential element of the ARIS concept.


EPC graphically depict work processes in a semi-formal modeling language with syntax rules . This is intended to systematize and parallelize operational processes in order to save time and money. Since decisions are made on the basis of conditions and rules within the process, there are link operators (“ and ”, “ or ”, “ exclusive-or ”) in the EPC . In addition to these operators, the basic model of the event-controlled process chain also includes events and functions. For this purpose, objects in directed graphs are connected with linking lines and arrows in a 1: 1 assignment (exception for logical links). In such a chain of connections, the objects alternate in their meaning between event and function, that is, they form an alternating sequence that leads to a bipartite graph.

Symbols and syntax rules

Topologically, process chains are directed graphs without a loop. The nodes are entities of an organization, methods of a process or auxiliary nodes of the structuring. The edges are information flows. Feedback or iterations are not visualized in this process. The chain's processes lead to a common business goal.

  • An event is a condition that occurs before or after a function. The symbol for an event is hexagonal. In the example above: "Order has been accepted".
  • A function (process) is an action or task that follows an event. Functions are symbolized by rectangles with rounded corners. In the example above: "Check order".
  • Connectors are used to split or unite the control flow . The three connectors AND, OR and XOR are available, each of which is shown in a small circle with the corresponding symbol.
  • Process signs are references to other processes. They are symbolized by a rectangle behind which a hexagon is hidden.
  • Information objects represent documents or other data storage devices. The symbol for an information object is a rectangle. Example: "customer database"
  • Organizational units (symbol: ellipse with a vertical line in front of the left edge) symbolize roles or people who are responsible for the process. Organizational units are linked to functions by a continuous line. Examples of organizational units are “customer” or “marketing department”.

Organizational units and information objects are symbols of the extended event-controlled process chains (eEPK). The flow of information between the individual symbols is shown by arrows. Functions and events have exactly one incoming and one outgoing arrow (exceptions: no directional edge goes in for initial events, no arrow goes out for end events). If several events are to lead to a function, connectors (for example AND) must be connected upstream.

Due to the thinking that events are passive and functions are active, the following applies: An event must not be split into two functions via an OR or an XOR connector, as an event has no decision-making power.

Extended event-driven process chain (eEPK)

Complex example of an eEPC model

The extended event-controlled process chain (eEPK) represents an extended form of the modeling method EPK. The logical processes of a business process shown in the EPK are expanded by the elements of organization, data and performance modeling using the eEPK. For example, each function can also be linked to an information object from which information is loaded or in which information is saved.

For example, additional information about executors, supporting systems, data used, files created, etc. can be added here, which establish a connection to other model views of the ARIS company. Furthermore, information objects are used (e.g. databases, customer data), which have an influence on functions (change) or can get information from them.

In the extended EPC, the capabilities of the EPC are essentially supplemented by the elements and relationships of the function assignment diagram. As part of the eEPK, it is then also possible to create images of data flows, organizational units or application systems.

The additional possible relationships between functions and other elements are also referred to as non-structure-forming relationships because they describe neither the functional structure nor the process structure of an organization. The edges that exist between the graphic objects are understood as roles in the EPC. For example, a connection between an organizational unit and a function represents the role of an organizational unit with regard to the execution of the function (for example, “carries out”, “is technically responsible”).

Areas of application

EPCs can be used for various tasks:

Extended event-controlled process chains (eEPKs) with their free placement of the elements on the drawing area are used in a very similar way and can represent the same facts as process chain diagrams (VKDs) with their column-wise sorting of the elements.

Advantages and disadvantages of the event-driven process chain


  • Event-controlled process chains offer advantages through the free placement of the elements on the drawing area when displaying alternative or parallel processes and when looping back as well as when using the existing drawing area.
  • Description of standardized processes possible
  • Very extensive tool support
  • Close proximity to standard software systems


  • When recognizing organizational breaks (change of organizational unit), system breaks (change of application system) or data breaks (change of data carrier or data format), event-driven process chains are at a disadvantage compared to process chain diagrams , because process chain diagrams offer a column-by-column sorting of the elements according to type.
  • Problems in mapping creative and complex activities
  • Problems in modeling surveillance and control activities
  • Recording of purely formal structures and processes
  • Compared to the BPMN , the EPK lacks standardization by a corresponding organization, which means that it is less widespread outside the German-speaking area.


  • G. Keller, M. Nüttgens, A.-W. Scheer: Semantic process modeling on the basis of "event-driven process chains (EPC)" . In: Saarland University (ed.): Publications of the Institute for Information Systems (IWi) . No. 89 . Saarbrücken January 1992 ( archive.org [PDF; accessed on October 28, 2019]).
  • Jörg Becker, Martin Kugeler, Michael Rosemann: Process Management - A Guide to Process-Oriented Organizational Design. 6th revised and expanded edition, Springer, Berlin 2008, ISBN 3-540-79248-1 .
  • Markus Nüttgens, Frank J. Rump: Syntax and semantics of event-driven process chains (EPK) (PDF; 364 kB) . In: J. Desel; M. Weske (Hrsg.): Promise 2002 - Process-oriented methods and tools for the development of information systems - Proceedings of the GI workshop and specialist group meeting (Potsdam, October 2002). Bonn 2002, pp. 64-77.
  • August-Wilhelm Scheer: ARIS - modeling methods, metamodels, applications . 4th edition, Springer, Berlin 2001, ISBN 3-540-41601-3 .
  • August-Wilhelm Scheer: ARIS - From business process to application system . 4th edition, Springer, Berlin 2002, ISBN 3-540-65823-8 .
  • August-Wilhelm Scheer: ARIS House of Business Engineering: From business process modeling to workflow-controlled application: from business process reengineering to continuous process improvement ( Memento from February 6, 2009 in the Internet Archive ) (PDF; 837 kB) . Published in the series: Publications of the Institute for Information Systems. A.-W. Scheer (ed.). Issue 133, Saarbrücken 1996.
  • Josef L. Staud: Business process analysis: event-driven process chains and object-oriented business process modeling for standard business software . 3rd edition, Springer, Berlin 2001, ISBN 3-540-24510-3 .

Individual evidence

  1. A.-W. Scheer (2002). ARIS. From business process to application system . Jumper. p.20.
  2. Cf. Oliver Kopp: Illustration of EPKs according to BPEL using the Nautilus process modeling tool. University of Stuttgart, Faculty of Computer Science, Electrical Engineering and Information Technology, Diploma Thesis No. 2341 (2005) ( Memento of the original from September 26, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. ; Simon / Freedom / Olbrich ( PDF ) @1@ 2Template: Webachiv / IABot / www.informatik.uni-stuttgart.de

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