Conceptualizing Requirements Using User Stories and Use Cases: A Controlled Experiment

Abstract

[Context and motivation] Notations for expressing requirements are often proposed without explicit consideration of their suitability for specific tasks. Consequently, practitioners may choose a sub-optimal notation, thereby affecting task performance. [Question/problem] We investigate the adequacy of two well-known notations: use cases and user stories, as a starting point for the manual derivation of a static conceptual model. In particular, we examine the completeness and correctness of the derived conceptual model. [Principal ideas/results] We conducted a two-factor, two-treatment controlled experiment with 118 subjects. The results indicate that for deriving conceptual models, user stories fit better than use cases. It seems that the repetitions in user stories and their conciseness contribute to these results. [Contribution] The paper calls for evaluating requirements notations in the context of various requirements engineering tasks and for providing evidence regarding the aspects that need to be taken into account when selecting a requirement notation.