Using business process models to better understand the dependencies among user stories

Context: Agile software development projects often manage user requirements with models that are called user stories. Every good user story has to be independent, negotiable, valuable, estimable, small, and testable. A proper understanding of a user story also requires an understanding of its dependencies. The lack of explicit representation of such dependencies presumably leads to missing information regarding the context of a user story. Objective: We propose a method that facilitates better understanding of execution order and integration dependencies of user stories by making use of business process models. The method associates user stories with the corresponding business process model activity element. Method: We adopted a situational method engineering approach to define our proposed method. In order to provide understanding of proposed method's constructs we used ontological concepts. Our method associates a user story to an activity element. In this way, the business process model can be used to infer information about the execution order and integration dependencies of the user story. We defined three levels of association granularity: a user story can be more abstract, approximately equal to, or more detailed than its associated business process model activity element. In our experiment we evaluate each of these three levels. Results: Our experiment uses a between-subject design. We applied comprehension, problem-solving and recall tasks to evaluate the hypotheses. The statistical results provide support for all of the hypotheses. Accordingly, there appears to be significantly greater understanding of the execution order and integration dependencies of user stories when associated business process models are available. Conclusions: We addressed a problem which arises from managing user stories in software development projects and focuses on the missing context of a user story. Our method contributes to the discipline of conceptual modeling in agile development. Our experiment provides empirical insight into requirement dependencies. (C) 2015 Elsevier B.V. All rights reserved.