Developing use cases and scenarios in the requirements process

Scenarios are often used for discovering requirements using established techniques, but how such scenarios are initially developed is not so well understood. This experience paper reports the application of one scenario-based approach - RESCUE - to discover requirements for DMAN, an air traffic management system for the UK's National Air Traffic Services. A retrospective analysis of the DMAN use cases, scenarios and requirements artifacts revealed the importance of diverse information sources in the specification of use cases that enabled systematic requirements discovery. Results were used to explore 3 research questions that arose in previous studies. The paper reports lessons from this experience and offers guidelines that practitioners can apply in their requirements processes and academics can use to inform their research.