J. Mending et aL./Information Systems 35(2010) 467-482 469 practice, a number of Table 1 typically suggest a verb- Distribution of activity label styles in the SAP reference model. I. ver 出 This convention is similar to a style that is advocated in Action-noun labels guidelines that support the creation of understandable 11830 1201 19.838 use case descriptions, a widely accepted requirements tool 60% in object-oriented software engineering [27, 28 We will refer to this labeling style of activities as the verb-object style. But as much promotion it receives in the process reference model overall, this situation does not imply that modeling domain, both anecdotal evidence and causal the verb-object style is strictly enforced within this inspection of real process models indicate that this subset. Rather, it is applied to only about two-third of labeling style is neither universally nor consistently the"action-oriented (60% of all activity labels ). The applied. Even the practical guide for process modeling n-oriented"labels (34% of with ARIS 29, pp 66-70 shows models with both actions all activity labels) labels where the action is as verbs and as nouns. Also, one may think that the more grammatically captured as a noun. This noun can be information contained in the labels. the clearer the either a gerund of the verb or a noun that is derived from a ning will be to the reader. Recent research, howeve verb, like order processing or invoice verification. We will uncovered that shorter activity labels improve model refer to this style of labeling as the action-noun style. The derstanding 30] overall result from classifying all 19, 838 activity labels can To get a better idea of the variety in labeling styles be seen in Table 1 being applied in practice, we turn to the SAP Reference We will now consider these data in more detail Model [31]. The development of the SAP reference model More precisely, for each of the labeling styles found, we started in 1992 and first models were presented perform a grammatical analysis using the lexical database 03 [31. p. Vll]. Since then, it was developed furthe yordNet [35 to identify potential types of interpretation ersion 4.6 of SAP R/3, which was released in 2000. ambiguity. This grammatical analysis builds on the the sap reference model includes 604 business identification of syntactic categories such as noun and process models depicted using the Event-driven Process verb. Further categories like adjective and adverb could Chains(Epc) notation, capturing information about the also be used but do not pertain to activity labeling in SAP R/ 3 functionality to support the business processes in process modeling, which is why we excluded these a wide range of organizations. With the SAP solution being categories from our analysis. For many words, the he market leading tool in the Enterprise Systems market syntactic category can be identified purely syntactically, we feel that the examination of SaP process models gives as for instance with the word grammar, which is a noun. us a good understanding of the use of process models in Some words, however, are ambiguous regarding the real-life business contexts. Amongst other application category they belong to(when analyzed in isolation). areas, the SaP reference model denotes a frequently used Consider the word design, which can be a verb (to design) tool in the implementation of SAP systems [32], and much or a noun( the design) depending on the grammatical literature has covered its development and use 31 context As these examples from natural language prod Furthermore, it is frequently referenced in research papers sing show, ambiguity can be a significant impediment to s a typical reference model and used in previous ease of understanding. In light of this observation we thus examinations of process modeling, e.g, [10, 33, 34 argue that those labeling styles should be considere together, the 604 EPC models in the SaP reference process modeling that are least susceptible to ambiguity. m include ctivity labels, which we all We illustrate our argument with examples from the SAP lly inspected and classified In 94% of these cases Reference Model: instances activity labels refer to a certain Verb-object labels: Most of the verb-object labels seem action that should be undertaken, such as check billing intuitively understandable to us. Still, there are some block or order execution. This is not so for 6% of the labels, cases that are ambiguous from a grammatical point of because they neither include a verb nor a noun that view: The English language allows for a so-called zero refers to an action, consider, for instance, status analysis derivation beyond the suffix -ize and the suffix (iy cash position. We will refer to this style as the rest derivation of verbs from nouns [36]. As a consequence, the same word can both be a noun and a verb. Consider Note that the epC models considered were designed for example, the labels measure processing, export license based on the functionality and the terminology of the SAP heck, and process cost planning. They have in common ystem which might create different biases. On the one that the first word can be a verb, but reading it as an hand, system terminology could potentially be less object describing an action is also possible. Measure models o compared to labeling in conceptual design processing could potentially refer to the processing of a n the other hand the labels could be more measure or to the measurement of a processing. The same precise than labels in conceptual modeling practice. Yet, observation holds for the other labels. Some of these neither the high frequency of verb-object styles nor the ambiguities can be resolved by considering context variety of labeling styles in use directly suggest such bias. information, such as the labels of the other activities Despite the wide proliferation of 18, 648"acti the same process model. If the verb-object style was oriented"labels of the 19, 838 activity labels in the Sap consistently used as a standard throughout a processpractice, a number of informal guidelines exist that typically suggest a verb–object convention (e.g., approve order, verify invoice) for labeling activities, e.g., [18–20]. This convention is similar to a style that is advocated in guidelines that support the creation of understandable use case descriptions, a widely accepted requirements tool in object-oriented software engineering [27,28]. We will refer to this labeling style of activities as the verb–object style. But as much promotion it receives in the process modeling domain, both anecdotal evidence and causal inspection of real process models indicate that this labeling style is neither universally nor consistently applied. Even the practical guide for process modeling with ARIS [29, pp. 66–70] shows models with both actions as verbs and as nouns. Also, one may think that the more information contained in the labels, the clearer the meaning will be to the reader. Recent research, however, uncovered that shorter activity labels improve model understanding [30]. To get a better idea of the variety in labeling styles being applied in practice, we turn to the SAP Reference Model [31]. The development of the SAP reference model started in 1992 and first models were presented at CEBIT’93 [31, p. VII]. Since then, it was developed further until version 4.6 of SAP R/3, which was released in 2000. Overall, the SAP reference model includes 604 business process models depicted using the Event-driven Process Chains (EPC) notation, capturing information about the SAP R/3 functionality to support the business processes in a wide range of organizations. With the SAP solution being the market leading tool in the Enterprise Systems market we feel that the examination of SAP process models gives us a good understanding of the use of process models in real-life business contexts. Amongst other application areas, the SAP reference model denotes a frequently used tool in the implementation of SAP systems [32], and much literature has covered its development and use [31]. Furthermore, it is frequently referenced in research papers as a typical reference model and used in previous examinations of process modeling, e.g., [10,33,34]. Altogether, the 604 EPC models in the SAP reference model include 19,838 activity labels, which we all manually inspected and classified. In 94% of these cases (18,648 instances), the activity labels refer to a certain action that should be undertaken, such as check billing block or order execution. This is not so for 6% of the labels, because they neither include a verb nor a noun that refers to an action, consider, for instance, status analysis cash position. We will refer to this style as the rest category. Note that the EPC models considered were designed based on the functionality and the terminology of the SAP system which might create different biases. On the one hand, system terminology could potentially be less intuitive compared to labeling in conceptual design models. On the other hand, the labels could be more precise than labels in conceptual modeling practice. Yet, neither the high frequency of verb–object styles nor the variety of labeling styles in use directly suggest such bias. Despite the wide proliferation of 18,648 ‘‘action￾oriented’’ labels of the 19,838 activity labels in the SAP reference model overall, this situation does not imply that the verb–object style is strictly enforced within this subset. Rather, it is applied to only about two-third of the ‘‘action-oriented’’ labels (60% of all activity labels). The remaining subset of the ‘‘action-oriented’’ labels (34% of all activity labels) denote labels where the action is grammatically captured as a noun. This noun can be either a gerund of the verb or a noun that is derived from a verb, like order processing or invoice verification. We will refer to this style of labeling as the action-noun style. The overall result from classifying all 19,838 activity labels can be seen in Table 1. We will now consider these data in more detail. More precisely, for each of the labeling styles found, we perform a grammatical analysis using the lexical database WordNet [35] to identify potential types of interpretation ambiguity. This grammatical analysis builds on the identification of syntactic categories such as noun and verb. Further categories like adjective and adverb could also be used but do not pertain to activity labeling in process modeling, which is why we excluded these categories from our analysis. For many words, the syntactic category can be identified purely syntactically, as for instance with the word grammar, which is a noun. Some words, however, are ambiguous regarding the category they belong to (when analyzed in isolation). Consider the word design, which can be a verb (to design) or a noun (the design) depending on the grammatical context. As these examples from natural language proces￾sing show, ambiguity can be a significant impediment to ease of understanding. In light of this observation we thus argue that those labeling styles should be considered in process modeling that are least susceptible to ambiguity. We illustrate our argument with examples from the SAP Reference Model: Verb–object labels: Most of the verb–object labels seem intuitively understandable to us. Still, there are some cases that are ambiguous from a grammatical point of view: The English language allows for a so-called zero derivation beyond the suffix -ize and the suffix (i)fy derivation of verbs from nouns [36]. As a consequence, the same word can both be a noun and a verb. Consider, for example, the labels measure processing, export license check, and process cost planning. They have in common that the first word can be a verb, but reading it as an object describing an action is also possible. Measure processing could potentially refer to the processing of a measure or to the measurement of a processing. The same observation holds for the other labels. Some of these ambiguities can be resolved by considering context information, such as the labels of the other activities in the same process model. If the verb–object style was consistently used as a standard throughout a process ARTICLE IN PRESS Table 1 Distribution of activity label styles in the SAP reference model. Verb–object labels Action-noun labels Rest Sum 11,830 6808 1201 19,838 60% 34% 6% 100% J. Mendling et al. / Information Systems 35 (2010) 467–482 469