Quality and Understandability of Use Case Models

Abstract

Use case models are used in object-oriented analysis for capturing and describing the functional requirements of a system. Use case models are also used in communication between stakeholders in development projects. It is therefore important that the use case models are constructed in such a way that they support the development process and promote a good understanding of the requirements among the stakeholders. Despite this, there are few guidelines on how to construct use case models.

This paper describes an explorative study where three different sets of guidelines were used for constructing and documenting use case models. An experiment with 139 undergraduate students divided into 31 groups was conducted. Each group used one out of the three sets of guidelines when constructing a use case model from an informal requirements specification. After completing the use case model, each student answered a questionnaire.

The results of the experiment indicate that guidelines based on templates support the construction of use case models that are easier to understand for the readers, than guidelines without specific details on how to document each use case. The guidelines based on templates were also considered as the most useful when constructing use cases. In addition to better understandability, our experiment indicates that the guidelines based on templates result in better use case models regarding also other quality attributes. Our results further indicate that it may be beneficial to combine the template guidelines with another set of guidelines that focus on the documentation of the flow of events of each use case.