Before any requirements are drafted you MUST come up with a problem statement to help focus all future requirement discussions. "How does this relate to the problem definition.
- Are all the inputs to the system specified, including their source, accuracy, range of values and frequency?
- Are all the outputs from the system specified, including their destination, accuracy, range of values, frequency and format?
- Are all output formats specified?
- Are all the external hardware and software interfaces specified?