Interrelating Use Cases and Associated Requirements by Links: An Eye Tracking Study on the Impact of Different Linking Variants on the Reading Behavior

[Context:] The descriptions of interactions and system functions are two of the most important artifact types in requirements specifications. Their common notations are use cases and requirements which are related to each other. There are different variants to link a use case with its associated requirements due to a wide variety of use case templates. The main purpose of all linking variants is to highlight the interrelationships between use cases and requirements. Besides considering both artifacts for themselves, a reader needs to interrelate them to achieve a high understanding of the overall content. [Objective / Method:] Due to the effort to create and maintain links, we investigated the impact of different linking variants on the reading behavior in an eye tracking study with 15 subjects. [Results:] Our findings indicate that all investigated variants cause comparable visual effort and share the most frequent sequential reading pattern. In all cases, the use case was read first and then the requirements. Nevertheless, the different variants result in divergent reading behaviors. Especially, links embedded in the table of a use case description significantly increase the number of attention switches from the use case to the requirements. [Conclusion:] These attention switches represent the reading behavior of interrelating the use case and the associated requirements which only occurred in case of the most detailed linking variant.