[Context and Motivation] User stories are a popular notation for representing requirements, especially in agile development. Although they represent a cornerstone for developing systems, limited research exists on how user stories are refined into low-level requirements and system design.

[Question/Problem] We study the process of deriving conceptual models from user stories, which can be at the basis of development paradigms such as low-code development. We focus our attention on the derivation of domain models (class diagrams) and use case diagrams. In this paper, we examine whether providing guidelines has an effect on the ability of humans to derive complete and valid conceptual models.

[Principal Ideas/Results] We design example-based guidelines for the derivation of class diagrams and use case diagrams from user stories. Then, we conduct a two-factor, two-treatment controlled experiment with 77 graduate students serving as subjects. The results indicate that the guidelines improve the completeness and validity of the conceptual models in cases of medium complexity, although the subjects do not perceive them as very useful.

[Contribution] The guidelines may assist analysts in the refinement process of user stories. Our initial evidence, besides showing how the guidelines can effectively help junior analysts derive high-quality conceptual models, opens the doors for further studies on the refinement of user stories, and to the investigation of alternative guidelines.