1. Faulty EPCs in the SAP Reference Model
Jan Mendling Vienna University of Economics
Michael Moser Vienna University of Economics
Gustaf Neumann Vienna University of Economics
Boudewijn van Dongen TU Eindhoven
Eric Verbeek TU Eindhoven
Wil van der Aalst TU Eindhoven

2. What is happening here?

3. Agenda EPCs and Errors The SAP Reference Model Finding Errors Results
Conclusion

4. Agenda
EPCs and Errors

5. EPCs as a Process Modeling Language
AND
Split
Join
XOR
EPC
Function
Event
Activity
Pre -
&
Post
condition OR

6. Problems with Connector Mismatch

7. The BPM Life cycle

8. The SAP Reference Model
Agenda
The SAP Reference Model

9. The SAP Reference Model
About 10,000 information models
5 Hierarchy Levels
29 Branches
Various model types: data, organization, processes, etc.
604 EPC business process models

10. An EPC Business Process Model

11. Using the SAP Reference Model
Change EPC Models
Change SAP System

12. Why Correct EPC Models? Misunderstandings in Teaching Processes
Comparing System with existing processes
Customization of System

13. Agenda
Finding Errors

14. How to find errors? Soundness (v.d.Aalst 1997):
For every state that is reachable from the start, the end can be reached.
If the end is reached, there is no activity still active.
All activities can be reached.
Relaxed Soundness (Dehnert, Rittgens 2001):
Every activity participates in a run from start to end.

15. Verification Approach

16. An EPC from the SAP Reference Model

17. Mapping to YAWL

18. The resulting YAWL net

19. Petri Net analysis within WofYAWL

20. Potential Correction

21. Agenda
Results

22. Results

23. Modeling Error 1: Deadlock

24. Modeling Error 2: Livelock

25. Why Errors Hypotheses: Model Size Model Complexity Error Patterns
Independent variables:
Number of each element type
Cycles
Complexity metrics based on state space
Logistic Regression:
Explain error (yes/no)
Nagelkerke R2: and 0.26 in significant models
Correct Classification: about 95%

26. Agenda
Conclusion

27. Conclusion Correctness is an issue in practice
Relaxed Soundness as a lower bound
At 5.6% of the models with errors
Model Complexity matters
Closer coupling of process models and enterprise system needed