Use Cases in a COTS Tender

When a customer buys a large standard system through a tender process, he has little influence on the detailed functionality. This calls for functional requirements on a high level. In this study of a large payroll and roster system, we have tried use cases as the requirements. They turn out to give both customer and supplier a better understanding of the demands, they don't favour one supplier over others, and they help elicit important requirements. To replace traditional requirements, they have to be supplemented with data models. Still some requirements are difficult to cover through use cases, e.g. those specifying complex screens for monitoring purposes.