Scenario-Driven Search Finds More Exceptions

Requirements elicitation tends to focus on stakeholders' primary goals, whether these are modelled as processes or use cases. However, exception cases often outnumber 'normal' cases and can drive project cost. This paper describes an experiment to see whether scenarios could effectively drive the search for exceptions. Experienced engineers asked to specifi a small system found three times as many exceptions by searching all scenario steps as by examining draft requirements.