J Mending et al./ Information Systems 35(2010)467-482 out, for instance, that examined the impact of process 2. Background model structure, model user competency and proces modeling language on process model understanding. In presenting the background to our research, we refer to While the impact of structural properties is clearly a theory of multimedia learning identified [10. it is also reported that model readers cience. This theory suggests that labeling practices are systematically overestimate their ability to draw correct indeed significant factors contributing to how well or how conclusions from a model [9]. It was also found that the poorly process models can be understood by their end users. choice of languages used for process modeling(e.g, BPMN To determine what a good labeling style is, we then identify versus EPCs) has only insignificant effects on proces different styles of labeling being used in practice. We model understanding [11]. Other research has successfully describe how the exploration of a large number of real-life cal constructs and their meaning process models gives us this insight One of the styles that is alidity encountered is the usage of verb-object labels. as this style n process models, e.g,[13. or is widely promoted in the literature [18-20], we formulate such as data and resources, e.g., several hypotheses on its presumed superiority over the [415 other styles encountered in our exploration. This situation raises the question of other antecedents of process model understandability. Most of the previous 2.1. Theoretical foundation york has focused on syntactic quality aspects [16]. In contrast, semantic and pragmatic aspects of model quality Dual Coding Theory [21] suggests that indiv have mostly been neglected. In particular, little attention two separate channels-visual and auditory-that they use has been devoted to a very essential task in process when processing information. The two channels comple modeling-the labeling of the graphical constructs, in particular of the constructs representing"activities"( ment each other, such that receiving simultaneous in- formation through each channel improves understanding compared to receiving information through one channel meaning of any construct in a process model is only revealed when model users read and intuitively under- material better when it is provided through both auditory tand the labels assigned to the construct. Current (i. e, words)and visual (ie, images)channels practice indicates that the labeling of activity constructs Based on this observation, the Cognitive Theory of is a rather arbitrary task in modeling initiatives and on Multimedia Learning(CTML)[23, 24] suggests that learn- ing material intended to be received, understood and that is sometimes done without a great deal of thought retained by its recipients should be presented using both [17. This can undermine the understandability of the resulting models in cases where the meaning of the labels words and pictures. This sounds conducive to the task of is ambiguous, not readily understandable, or simply process modeling, where both visual (graphical con- structs) and audit labels and text annotations counter-intuitive to the reader material are available to add information about a business Accordingly, in our work we seek to address this gap domain in a process model. However, due to the overall nd contribute to the existing line of work towards more limited number of graphical constructs used in a process understandable process models. The objective of our model-there are typically few if not only one graphical research is to investigate the styles that are in use to annotate activities in process models construct for representing activities-most of the critical affect the understandability of such models. More domain information is contained in the textual labels the constructs, viz., in auditory channels Based on CTML it precisely. the aim of this paper is to suggest, based on can thus be expected that model understanding can be our e pirical findings, an imperative style for modelers to create more understandable process models improved if better guidance can be provided for the act of We proceed as follows. In Section 2 we discuss abeling of process model constructs. the theoretical foundation for our work and investi- he general principle that our expectation builds on is described by Mayer[24 as the"multimedia principal" And Section 3 we discuss the design of conduct of and indeed,prior research on conceptual modeling has success. findings from an experiment with process modelers. In model understanding Empirically observable differences in Section 4 we then discuss the implications of our findings model understanding based on the multimedia principal nd suggest specific programs of research towards better support for process model labeling practices. We conclude were found, for instance, in the data modeling domain in Section 5 by reviewing our contributions, and discuss- [25, 26 as well as in the process modeling domain 11 2. 2. Labeling styles in practice For business process modeling, the labeling of con- i We recognize the need to extrapolate our research to other aspects structs such as activities is often more art than science. In the data. resource and control flow rspective. We deemed the focus on"activity constructs"a suitabl starting point for our endeavor due to the centrality of the"activity" 2 Indeed, most people read by speaking out the words of the text in their mind, which even suppresses visual activation [22out, for instance, that examined the impact of process model structure, model user competency and process modeling language on process model understanding. While the impact of structural properties is clearly identified [10], it is also reported that model readers systematically overestimate their ability to draw correct conclusions from a model [9]. It was also found that the choice of languages used for process modeling (e.g., BPMN versus EPCs) has only insignificant effects on process model understanding [11]. Other research has successfully investigated the graphical constructs and their meaning in process models, e.g., [12], the expressiveness and validity of control flow aspects in process models, e.g., [13], or process-related aspects such as data and resources, e.g., [14,15]. This situation raises the question of other antecedents of process model understandability. Most of the previous work has focused on syntactic quality aspects [16]. In contrast, semantic and pragmatic aspects of model quality have mostly been neglected. In particular, little attention has been devoted to a very essential task in process modeling—the labeling of the graphical constructs, in particular of the constructs representing ‘‘activities’’ (or ‘‘tasks’’, or ‘‘work to be performed’’) in a process model. This is rather surprising given that—clearly—the true meaning of any construct in a process model is only revealed when model users read and intuitively under￾stand the labels assigned to the construct. Current practice indicates that the labeling of activity constructs is a rather arbitrary task in modeling initiatives and one that is sometimes done without a great deal of thought [17]. This can undermine the understandability of the resulting models in cases where the meaning of the labels is ambiguous, not readily understandable, or simply counter-intuitive to the reader. Accordingly, in our work we seek to address this gap and contribute to the existing line of work towards more understandable process models. The objective of our research is to investigate the styles that are in use to annotate activities in process models and how these styles affect the understandability of such models.1 More precisely, the aim of this paper is to suggest, based on our empirical findings, an imperative style for modelers to create more understandable process models. We proceed as follows. In Section 2 we discuss the theoretical foundation for our work and investi￾gate current labeling practices in process modeling. In Section 3 we discuss the design of, conduct of, and findings from an experiment with process modelers. In Section 4 we then discuss the implications of our findings and suggest specific programs of research towards better support for process model labeling practices. We conclude in Section 5 by reviewing our contributions, and discuss￾ing some conclusions. 2. Background In presenting the background to our research, we refer to a theory of multimedia learning originating from cognitive science. This theory suggests that labeling practices are indeed significant factors contributing to how well or how poorly process models can be understood by their end users. To determine what a good labeling style is, we then identify different styles of labeling being used in practice. We describe how the exploration of a large number of real-life process models gives us this insight. One of the styles that is encountered is the usage of verb–object labels. As this style is widely promoted in the literature [18–20], we formulate several hypotheses on its presumed superiority over the other styles encountered in our exploration. 2.1. Theoretical foundation Dual Coding Theory [21] suggests that individuals have two separate channels—visual and auditory—that they use when processing information. The two channels comple￾ment each other, such that receiving simultaneous in￾formation through each channel improves understanding compared to receiving information through one channel only. In other words, individuals understand informational material better when it is provided through both auditory (i.e., words) and visual (i.e., images) channels.2 Based on this observation, the Cognitive Theory of Multimedia Learning (CTML) [23,24] suggests that learn￾ing material intended to be received, understood and retained by its recipients should be presented using both words and pictures. This sounds conducive to the task of process modeling, where both visual (graphical con￾structs) and auditory (labels and text annotations) material are available to add information about a business domain in a process model. However, due to the overall limited number of graphical constructs used in a process model—there are typically few if not only one graphical construct for representing activities—most of the critical domain information is contained in the textual labels of the constructs, viz., in auditory channels. Based on CTML it can thus be expected that model understanding can be improved if better guidance can be provided for the act of labeling of process model constructs. The general principle that our expectation builds on is described by Mayer [24] as the ‘‘multimedia principal’’. And indeed, prior research on conceptual modeling has success￾fully demonstrated that the multimedia principal informs model understanding. Empirically observable differences in model understanding based on the multimedia principal were found, for instance, in the data modeling domain [25,26] as well as in the process modeling domain [11]. 2.2. Labeling styles in practice For business process modeling, the labeling of con￾structs such as activities is often more art than science. In ARTICLE IN PRESS 1 We recognize the need to extrapolate our research to other aspects of process models, such as the data, resource and control flow perspective. We deemed the focus on ‘‘activity constructs’’ a suitable starting point for our endeavor due to the centrality of the ‘‘activity’’ concept in process modeling. 2 Indeed, most people read by speaking out the words of the text in their mind, which even suppresses visual activation [22]. 468 J. Mendling et al. / Information Systems 35 (2010) 467–482