Improving Comprehension of Process Diagrams with Graphical Highlights

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Business processes are core assets of organizations, and they re ect what companies do when they deliver services or products to customers. As such, an organization can outperform its competitors if it has more e ective processes and executes them more e ciently [ 5, 10 ]. This is reasonable, since process-oriented structures help organizations to adapt to the increasingly changing environment [ 20 ].

Business processes can be represented in the form of business process models, which capture both how the business works, and how the value is created for various stakeholders [ 20 ]. In this regard, business process models aid in the communication between the stakeholders, thus, they must be easy to understand [ 9 ]. While business process models can be represented by means of textual description, it is a common practice to depict them graphically [ 3 ] with business process diagrams [ 5 ].

There are many visual languages for representing business processes diagrammatically. However, choosing the most appropriate visual language for diagrammatic modeling is not a guarantee for a more e ective communication between the stakeholders. The e ectiveness of such communication is in uenced mainly by how the intended message (i.e., how the modeler understands a diagram) matches the received message (i.e., how the reader understands the same diagram) [ 15 ]. This can become challenging to achieve, as business process diagrams can easily become large and di cult to understand [ 19 ]. This is often due to the complexity of the nature of the problem, which is re ected directly in the business process diagrams. On the other hand, they can also become unnecessarily complex, since one behavior can be modeled in di erent ways [ 11 ]. Indeed, one of the most common mistakes when modeling diagrams is to display too much information on a single diagram, which increases the diagram's complexity needlessly [ 14 ]. Incorrect understanding of business process diagrams can cause a variety of issues [ 1 ], e.g., inadequate implementation of the corresponding supporting systems and other design aws [ 11 ]. Complex business process diagrams can also become a barrier rather than an aid to communication with stakeholders [ 14 ], and can make it harder to determine if they capture the business practices correctly [ 18 ]. Considering this, we can conclude that the complexity of a diagram directly a ects its comprehensibility [ 11, 13 ] (sometimes used as a synonym for understandability [ 4 ]), since there are limits in human cognitive capabilities to make sense of complex diagrams [ 19 ].

In this light, cognitive e ectiveness of diagrams was de ned as the speed, ease, and accuracy with which a model representation can be processed by the human mind [ 14 ]. However, cognitive e ectiveness is not an inherent property of diagrams, but it must be designed into them. To this end, nine principles for creating cognitively e ective diagrams were proposed, namely [ 14 ]: 1. Discriminability, 2. Manageable complexity, 3. Emphasis, 4. Cognitive integration, 5. Perceptual directness, 6. Structure, 7. Identi cation, 8. Visual expressiveness, and 9. Graphic simplicity.

Some of these principles are already integrated in the diagramming notations, e.g., Business Process Model and Notation (BPMN) has built-in mechanisms for managing complexity in the form of Link Events for achieving modularization and Sub-Processes for hierarchic structuring [ 8 ]. Regardless of these built-in mechanisms, managing complex business process diagrams is a task that is still fraught with challenges [ 18 ]. This might also be because, according to Moody [ 14 ], the design of diagramming notations is mostly unscienti c and based on personal taste or intuition. Indeed, some of the most predominant diagramming notations that enable modeling of business process diagrams are perceived as being complex and not easy to learn, even for business analysts [ 6 ]. Similarly, modelers are typically not instructed on how to create cognitively e ective diagrams, hence, they rely on their intuition and experience. As such, the resulting diagrams might distort the information, or even convey unintentional messages [ 14 ]. Hence, it is reasonable that there is a considerable body of literature regarding the cognitive e ectiveness of business process diagrams. These studies commonly apply the aforementioned principles for creating cognitively e ective diagrams by leveraging the extensibility of the elements' non-standardized visual variables for displaying di erent kinds of information. This is also known as secondary notation [ 15 ], which can improve the comprehension of diagrams (e.g., associating a speci c color with an organization's role [ 17 ]). Other studies propose extensions of the existing diagramming notations [ 21 ], which do not violate the speci cation, but they change the corresponding metamodel (e.g., simplifying temporal constructs in order to increase readability [ 7 ]).

To summarize the above, the main purpose of business process diagrams is to facilitate the communication between the process-related stakeholders, which directly a ects the decision-making. For this reason, they must be easy to understand. However, this is often challenging to achieve, since business process diagrams can become large and complex. In this light, the low level of modeling competence in a casual modeler has been recognized as one of the main causes that process diagrams lack in quality [ 12 ]. The common modeling mistakes can make diagrams a barrier instead of an aid to communication [ 14 ], and poorly designed diagrams may be even less e ective than text [ 16 ]. To this end, many frameworks, principles and guidelines for modeling were proposed. While they commonly lack a sound research foundation, or are too abstract [ 12 ], several attempts were made to provide empirically-based and operational guidance for both designers and users of diagrams, e.g.: [ 14, 12, 2 ]. However, the majority of these approaches intervene in the diagramming notations' speci cations or the business process diagrams' de nition. As such, they require that the information of applied principle is stored either in the process diagram's model or the diagramming notation's metamodel. This can cause several issues, e.g., interoperability and compatibility between the diagrammatic tools is hindered [ 17 ]. Furthermore, overuse of speci c approaches (e.g., Graphical Highlight pattern [ 18 ]) may lead to potentially unreadable process diagrams [ 18 ].

Based on these challenges, the goal of this doctoral thesis was to propose and investigate a non-intrusive approach that makes business process diagrams appear less complex, without changing the corresponding diagrammatic notation or the business process diagrams themselves. This was done by manipulating the opacity of graphical elements in order to emphasize the important parts of a business process diagram by lowlighting the irrelevant ones. The proposed solution, named Emphasis, implemented with opacity-based Graphical Highlight pattern, abbreviated as simply Graphical highlights, introduces six Structural and seven Behavioral Graphical highlights.

Graphical highlights were rstly applied to a sample business process diagram, modeled in Business Process Model and Notation (BPMN). The analysis addressed the real-world procedure, and based on the survey of the process, we applied one representative of Structural and one representative of Behavioral Graphical highlight, respectively, to the conventional process diagram. Afterwards, the complexity analysis of all three process diagrams was performed. Based on the results of the analysis, we can conclude that the application of either Structural or Behavioral Graphical highlights decreased the complexity of the highlighted part of the process diagram in almost all of the observed measures. In several cases this meant that understandability of the process diagram increased.

Afterwards, a Web application prototype was implemented, which supports the proposed set of Graphical highlights. The prototype can render the business process diagrams and provide the support for both categories of the aforementioned Graphical highlights. The back end of the prototype was implemented in PHP: Hypertext Preprocessor programming language, while the front end is served using the AngularJS, a JavaScript open-source web application framework, and Bootstrap, a framework for developing responsive and mobile-friendly Graphical User Interfaces (GUIs).

Furthermore, we empirically validated whether Graphical highlights positively impact cognitive e ectiveness of business process diagrams, and if the users will nd the prototype implementation useful. To this end, an experimental research, which included 85 participants, was conducted. The participants were randomly assigned in either the treatment group (Graphical highlights diagram representation approach), or the control group (conventional diagram representation approach). In accordance with the de nition of cognitive e ectiveness, speed, ease, and accuracy of answering 26 comprehension questions were observed, along with the perceived usefulness of the prototype. The results of the analysis demonstrated that participants who used Graphical highlights signi cantly outperformed those that used the conventional approach in all experiment's observations.

We can conclude that using Graphical highlights increases the cognitive effectiveness of business process diagrams, while the corresponding prototype implementation is perceived as being useful by the experiment's participants. The results supplement the related work, which demonstrated that the color-based Graphical Highlight pattern is perceived as useful and increases the ease of use. However, conversely from the related work, Graphical highlights do not interfere with either the diagramming notations or with the process diagrams. Since process diagrams are valuable organizational assets that facilitate decision-making activities and communication, we consider Graphical highlights as a cognitive e ective mechanism that simpli es those activities further.

References

1. Cardoso , J. , Mendling , J. , Neumann , G. , Reijers , H.A. : A Discourse on Complexity of Process Models . In: Proceedings of the 2006 International Conference on Business Process Management Workshops . pp. 117 { 128 . BPM'06, SpringerVerlag , Berlin, Heidelberg ( 2006 ). https://doi.org/10.1007/11837862 13, http: //dx.doi.org/10.1007/11837862{\_} 13

2. Corradini , F. , Ferrari , A. , Fornari , F. , Gnesi , S. , Polini , A. , Re , B. , Spagnolo , G.O.: A Guidelines framework for understandable BPMN models . Data & Knowledge Engineering 113 , 129 { 154 ( 2018 ). https://doi.org/https://doi.org/10.1016/j.datak. 2017 . 11 .003, http://www. sciencedirect.com/science/article/pii/S0169023X1630341X

3. DaSilva , C.M. , Trkman , P. : Business Model: What It Is and What It Is Not. Long Range Planning 47 ( 6 ), 379 { 389 ( 2014 ). https://doi.org/https://doi.org/10.1016/j.lrp. 2013 . 08 .004, http://www. sciencedirect.com/science/article/pii/S0024630113000502

4. Dikici , A. , Turetken , O. , Demirors , O. : Factors in uencing the understandability of process models: A systematic literature review . Information and Software Technology 93 , 112 { 129 ( 2018 ). https://doi.org/https://doi.org/10.1016/j.infsof. 2017 . 09 .001, http://www. sciencedirect.com/science/article/pii/S0950584916302889

5. Dumas , M. , Rosa , M.L. , Mendling , J. , Reijers , H.A. : Fundamentals of Business Process Management . Springer Publishing Company, Incorporated ( 2013 )

6. Fernandez , H.F. , Palacios-Gonzalez , E. , Garc a-D az , V., Pelayo G -Bustelo, B.C. , Sanjuan Mart nez, O., Cueva Lovelle , J.M.: SBPMN - An Easier Business Process Modeling Notation for Business Users . Comput. Stand. Interfaces 32 ( 1-2 ), 18 { 28 (Jan 2010 ). https://doi.org/10.1016/j.csi. 2009 . 04 .006, http://dx.doi.org/10. 1016/j.csi. 2009 . 04 .006

7. Gagne , D. , Trudel , A. : Time-BPMN . In: Proceedings of the 2009 IEEE Conference on Commerce and Enterprise Computing . pp. 361 { 367 . CEC '09, IEEE Computer Society, Washington, DC, USA ( 2009 ). https://doi.org/10.1109/CEC. 2009 . 71 , http://dx.doi.org/10.1109/CEC. 2009 .71

8. Genon , N. , Heymans , P. , Amyot , D. : Analysing the Cognitive E ectiveness of the BPMN 2.0 Visual Notation . In: Proceedings of the Third International Conference on Software Language Engineering . pp. 377 { 396 . SLE' 10 , Springer-Verlag, Berlin, Heidelberg ( 2011 ), http://dl.acm.org/citation.cfm?id= 1964571 . 1964605

9. Gruhn , V. , Laue , R.: Complexity metrics for business process models . In: 9th international conference on business information systems (BIS 2006 ). vol. 85 , pp. 1 { 12 ( 2006 )

10. Kunze , M. , Luebbe , A. , Weidlich , M. , Weske , M. : Towards Understanding Process Modeling { The Case of the BPM Academic Initiative . In: Dijkman, R. , Hofstetter , J. , Koehler , J . (eds.) Business Process Model and Notation: Third International Workshop, BPMN 2011, Lucerne, Switzerland, November 21-22 , 2011 . Proceedings, pp. 44 { 58 . Springer Berlin Heidelberg, Berlin, Heidelberg ( 2011 ). https://doi.org/10.1007/978-3- 642 -25160-3 4, https://doi.org/10.1007/ 978-3- 642 -25160-3{\_} 4

11. Lassen , K.B., van der Aalst , W.M.P. : Complexity Metrics for Work ow Nets . Inf. Softw. Technol . 51 ( 3 ), 610 {626 (Mar 2009 ). https://doi.org/10.1016/j.infsof. 2008 . 08 .005, http://dx.doi.org/10.1016/j. infsof. 2008 . 08 .005

12. Mendling , J. , Reijers , H., van der Aalst, W.: Seven process modeling guidelines (7PMG) . Information and Software Technology 52 ( 2 ), 127 { 136 ( 2010 ). https://doi.org/https://doi.org/10.1016/j.infsof. 2009 . 08 .004, http://www. sciencedirect.com/science/article/pii/S0950584909001268

13. Mendling , J. , Reijers , H.A. , Cardoso , J.: What Makes Process Models Understandable? In: Proceedings of the 5th International Conference on Business Process Management . pp. 48 { 63 . BPM' 07 , Springer-Verlag, Berlin, Heidelberg ( 2007 ), http://dl.acm.org/citation.cfm?id= 1793114 . 1793120

14. Moody, D.: What Makes a Good Diagram? Improving the Cognitive E ectiveness of Diagrams in IS Development . In: Wojtkowski, W. , Wojtkowski , W.G. , Zupancic , J. , Magyar , G. , Knapp , G . (eds.) Advances in Information Systems Development: New Methods and Practice for the Networked Society . pp. 481 { 492 . Springer US , Boston, MA ( 2007 ). https://doi.org/10.1007/978-0- 387 -70802-7 40, https://doi. org/10.1007/978-0- 387 -70802-7{\_} 40

15. Moody, D.: The \Physics" of Notations: Toward a Scienti c Basis for Constructing Visual Notations in Software Engineering . IEEE Transactions on Software Engineering 35 ( 6 ), 756 {779 (Nov 2009 ). https://doi.org/10.1109/TSE. 2009 .67

16. Moody, D., van Hillegersberg, J. : Evaluating the Visual Syntax of UML: An Analysis of the Cognitive E ectiveness of the UML Family of Diagrams . In: Gasevic, D. , Lammel, R., Van Wyk , E . (eds.) Software Language Engineering . pp. 16 { 34 . Springer Berlin Heidelberg, Berlin, Heidelberg ( 2009 )

17. Muller, R., Rogge-Solti , A. : BPMN for healthcare processes . In: Proceedings of the 3rd Central-European Workshop on Services and their Composition (ZEUS 2011 ), Karlsruhe, Germany ( 2011 )

18. Rosa , M.L. , ter Hofstede , A.H.M. , Wohed , P. , Reijers , H.A. , Mendling , J., van der Aalst, W.M.P. : Managing Process Model Complexity via Concrete Syntax Modications . IEEE Transactions on Industrial Informatics 7 ( 2 ), 255 {265 (May 2011 ). https://doi.org/10.1109/TII. 2011 .2124467

19. Smirnov , S. , Reijers , H.A. , Weske , M.: A Semantic Approach for Business Process Model Abstraction . In: Mouratidis, H. , Rolland , C. (eds.) Advanced Information Systems Engineering: 23rd International Conference, CAiSE 2011 , London, UK, June 20-24, 2011 . Proceedings. pp. 497 { 511 . Springer Berlin Heidelberg, Berlin, Heidelberg ( 2011 ). https://doi.org/10.1007/978-3- 642 -21640-4 37, https: //doi.org/10.1007/978-3- 642 -21640-4{\_} 37

20. Trkman , M. , Mendling , J. , Krisper , M. : Using Business Process Models to Better Understand the Dependencies Among User Stories . Inf. Softw. Technol . 71(C), 58 { 76 (Mar 2016 ). https://doi.org/10.1016/j.infsof. 2015 . 10 .006, http://dx.doi.org/ 10.1016/j.infsof. 2015 . 10 .006

21. Yous , A. , Bauer , C. , Saidi , R. , Dey , A.K. : uBPMN: A BPMN extension for modeling ubiquitous business processes . Information and Software Technology 74 ( Supplement C) , 55 { 68 ( 2016 ). https://doi.org/https://doi.org/10.1016/j.infsof. 2016 . 02 .002, http://www. sciencedirect.com/science/article/pii/S0950584916300209