Improving the Quality and the Comprehension of Requirements: Disciplined Use Cases and Mockups

In this paper we sketch a novel method for writing requirements specifications that enriches disciplined use cases with screen mock-ups. Disciplined use cases are characterized by a quite stringent template, strongly structuring also the form of the scenarios´ steps (e.g., The subject of each step must be explicit). That structuring allows to impose further constraints helping to prevent common mistakes and to increase the quality of the specifications (e.g., Defining a detailed glossary helps to avoid confusion and ambiguities). Disciplined use case are still expressed using natural language, but the strong structuring allows to reach a good level of precision without having to introduce new notations. Screen mock-ups associated with the scenarios´ steps, present the corresponding GUIs as seen by the human actors before/after the step executions, improving the comprehension of the requirements, and allowing also to precisely present user interface´s non-functional requirements.