1. 1
Analysis of Most Common Process
Modelling Mistakes in BPMN Process Models
dr. Tomislav Rozman, Gregor Polančič, doc. dr. Romana Vajde Horvat
26. – 28. September 2007
Potsdam, Germany
Faculty of Electrical
Engineering and Computer
Science
University of Maribor, Slovenia
Institute of Informatics

2. 2
Contents of the article
Introduction
 What is Business Process Management &
Modelling
 A little bit of history
 Similar work
Research method
Findings – process model antipatterns
Conclusions
Discussion

3. 3
What is Business Process
management?
... a field of knowledge at the intersection between
management and information technology,
encompassing methods, techniques and tools to
design, enact, control, and analyze operational
business processes involving humans, organizations,
applications, documents and other sources of
information1 or
...most overused word in the last few years?
1 van der Aalst, W.M.P., ter Hofstede, A.H.M. and Weske, M.: "Business Process Management: A Survey", in Business Process Management,
Proceedings of the First International Conference. Springer Verlag, 2003.

4. 4
Business process management /
business process lifecycle
Preparation
+
BP Modelling
+
BP Assessment
+
BP
Dissemination
+
Report a
'lesson learned'
Compare and
align with
business goal
BP
Implementation
+
no
yes
is responsible for
is responsible for
Defined process
needed
are responsible for
is responsible for
is responsible for
is responsible for
is responsible for
is responsible for
is responsible for
collaborate
Quality
Manager
Process
Performers
Process
Designer
Quality
Manager
IT Expert
Process
Owner
Process
Owner
Process
Performers
Process
Owner
Automate
the
process?
BP Usage BP tracking
& analysing
BP not needed
anymore
BP tailoring
needed
Performing BP

5. 5
What is (Business) Process
modelling?
Better: Discrete process modelling
Goal: to capture the knowledge how people
(machines) perform their work (or, how we would like
them to perform it)
Main purpose: to ensure at least repeatability of
organisation's processes
Plethora of methods, methodologies, notations,…
... but no silver bullet

6. 6
... Some process modelling
notations
EPC,
ARIS,
UML Activity diagrams,
OPM – Object Process Methodology,
BPMN – Business Process Modelling notation
Ontologically most complete (Recker et al, 2005)

7. 7
BPMN notation
Visual representation of (business) processes - workflow
It defines graphical symbols and additional attributes for
process description
Covers the process modelling concepts and patterns very well
Easy to learn
Based on: EPC, Petri nets, Activity diagrams (UML)
Defines the mapping to execution languages (XPDL, BPEL4WS)
Merging with UML?

8. 8
A quick introduction to BPMN notation (1/2)
name name name
~
name
~
name name
name
Sequence
Message flow
Association
name, condition,
code or message
name or message
Atomic activity - task Looping activity Ad-hoc process
Looping ad-hoc process Process (hidden details) Looping process (hidden details)
Process with details
Branching (parallel execution)
A
B
C D
Data-based OR-decision
A
B
C
D
condition
1
condition
2
default
Event-based OR-decision
A
B
C
D
1 day
mssage 1
message 2
Merging
A
B
C
D

9. 9
A quick introduction to BPMN notation (2/2)
name or source
name or type
name or result
Start
event
End
event
Intermediate
event
Message Timer Process
error
Compensate Rule Link Multiple
mesage
Pool
name
mesage
message
 events
gateways 
pools and
messages

10. 10
A little bit of history
BPMN notation has been taught since 2001 (University of
Maribor, Faculty of electrical engineering and computer
science)
BSc. Students of Information Systems, 8th semester
“Information processing organization and management”
practical lectures
The aim: (business) processes modeling, software
standards, software projects organisation
The modeling tool: Modified Microsoft Visio (‘’in-house’
symbols stencil)

11. 11
Similar work
Project ‘anti-pattern’
 = a pitfall, or, set of classes of commonly-
reinvented bad solutions to problems
 = commonly repeated bad practices
workflow patterns
 control flow patterns, resource patterns,
data patterns and exception handling
patterns

12. 12
The problem
BPMN does not prevent us to design bad
process models, including syntactical,
semantic and pragmatically errors.
Poor quality of process models can cause
poor quality software requirements resulting
in a poor information system.

13. 13
Research method
Research question: What are the most common mistakes
when modelling business process diagrams using BPMN
notation?
a multiple case study research
Analysis of the process models (designed by students) from
2002 to 2007 by three independent persons
Extraction & classification of most common mistakes -> process
anti-pattern
Syntactical, semantic and pragmatic mistakes

14. 14
Findings
A set of 15 proces model anti-patterns
 Connecting elements (1-9)
 Other mistakes (9-15)
Description of the antipatterns:
 Name,
 Possible practical impacts,
 Type of error,
 Proposed solution.

15. 15
Pattern 1. Activities in one
pool are not connected
PoolAPoolB
Task C Task D
Task A Task B ...
...
...
...
Fig. 1. Anti-pattern: Activities in one pool
are not connected
PoolAPoolB
Task C Task D
Task A Task B ...
...
...
...
Fig. 2. Correct pattern

16. 16
Pattern 2. Process does not
contain a start eventPoolA
Task A Task B ...
Message Event
Fig. 1. Anti-pattern: Process does not
contain a start event
PoolA
Task A Task B ...
Message Event
Start Event
Fig. 2. Correct pattern

17. 17
Pattern 3. Process does not
contain an end event
PoolA
Task A
Task B...
Task C
Fig. 1. Anti-pattern: Process does not
contain an end event PoolA
Task A Task B...
Task C
End event
Terminate
Fig. 2. Correct pattern

18. 18
Pattern 4. Sequence flow
crosses process boundary
Process X
Task A Task B...
...
Task C
Fig. 1. Anti-pattern: Sequence flow crosses
process boundary
Process X
Task A
Task B
...
...
Task C
Fig. 2. Correct pattern

19. 19
Pattern 5. Sequence flow
crosses pool boundary
PoolA
Task A Task C
PoolB
Task B Task D
Message flow AB Message flow DC
Task E
Task F
...
...
End event
Start Event
Fig. 1. Anti-pattern: Sequence flow
crosses pool boundary
PoolA
Task A Task C
PoolB
Task B
Task D
Message flow AB
Message flow DC
Task E
Task F
Message flow EF
......
......
Start Event
End event
End event
Start Event
Fig. 2. Correct pattern

20. 20
Pattern 6. Gateway receives,
evaluates or sends a message
PoolA
Task A Task B ......
Message X Message Y
Condition
Task C ...
PoolB
Fig. 1. Anti-pattern: Gateway receives,
evaluates or sends a message
PoolA
Task A
Task B ...
...
Message X MessageY
Condition
Task C ...
Analysing
message X
Send
message Y
...
PoolB
Fig. 2. Correct pattern

21. 21
Pattern 7. Intermediate events are
placed on the edge of the pool
PoolA
Task A Task B
Start event
End event
Intemediate
event M1
Intermediate
event M2
Fig. 1. Anti-pattern: Intermediate events
are placed on the edge of the pool
PoolB
Task A Task B
Start event
End event
Intemediate
event M1
Intemediate
event M2
Fig. 2. Correct pattern

22. 22
Pattern 8. Hanging intermediate
events or activities
PoolA
Task A Task c
Start event
End event
Intermediate event
Task B
Fig. 1. Anti-pattern: Hanging
intermediate events or activities PoolB
Task A Task C
Start event End event
Intermediate event
Task B
Fig. 2. Correct pattern

23. 23
Pattern 9. Each lane in the
pool contains start event
Start event 1
Task A
End event
Start event 2
Task B
End event
Start event 3
Task C
End event
Lane1Lane2Lane3
PoolA
Fig. 1. Anti-pattern: Each lane in the pool contains start event
Start event 1
Task A
End event
Task B
Task C
Lane1Lane2Lane3
PoolA
Lane1Lane2Lane3
PoolA
Task A
End event
Task B
End event
Task C
End event
Start event
Start event 1
Start event 2
Start event 3
Fig. 1. Two possibilities of correct patterns

24. 24
Pattern 10. Incorrect use of
time events
Task A Task B...
Task B ...
Delay
Exception
Time event used as a
DELAY mechanism
Time event representing
task DURATION
Fig. 1. : Anti-pattern: Incorrect use of time events
Solution: the meaning!

25. 25
Pattern 11. Sequence and message
event represent data flow
Task A Task B ......
Message
AB
Fig. 1. Anti-pattern: Sequence and
message event represent data flow
Task A Task B ......
Message
AB
Fig. 2. Correct pattern

26. 26
Pattern 12. Event is used as a
message flow source
Task A Task B ......
Message
A Message
B
A
B
Fig. 1. Anti-pattern: Event is used as a
message flow source
Task A
Send
message B
......
Message
A
Message
B
Task C
Fig. 2. Correct pattern

27. 27
Pattern 13. Improper use of
flow elements
Starting task
A
Receiving
document X
...
Task A
finished
Document
X
...
Fig. 1. Anti-pattern: Improper use of flow
elements
Task A... ...
Document
X
Event X
Fig. 2. Correct pattern

28. 28
Pattern 14. Starting timer placed
instead of intermediate timer
Task A...
...
Duration
Fig. 1. Anti-pattern: Starting timer
placed instead of intermediate timer
Task A...
...
Duration
Fig. 2. Correct pattern

29. 29
Pattern 15. Exception flow is not
connected to the exception
Task A... ...
Duration
Fig. 1. Anti-pattern: Exception flow is
not connected to the exception
Task A...
...
Duration
...
Normal flow
Exception flow
Fig. 2. Correct pattern

30. 30
Frequencies of the anti-patterns
appearance
1
2
4
5
6
7
89
10
11
12
13
14
15
3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Exception is modelled, but not
connected 
 Process does not
contain a end event
Sequence flow crosses
process boundary
 Hanging intermediate events or
activities
Starting timer placed instead of
intermediate timer 

31. 31
Conclusions
We identified unique collection of most common
process modelling mistakes or anti-patterns
Possible practical problems:
 unwanted delays in the process performance,
 non-execution of the activities or
 simply ambiguity which could hinder the process
performers at their work
Practical implications:
 Improvement of the learning materials
 Design of A2 poster with anti-patterns & solutions
 Possible improvement of the BPMN
 Improvements of BPMN modelling tool: verification!

32. 32
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Recieve a
question
Answer the
question
Ask a question
Bored=true
Coffe break
Start of the
discussion
Does a question
make any sense?
yes
no
Mumble or smile
J
Discussion

33. 33

34. Last but not least
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