How do you collect Marketing's requirements?
The industry is filled with anecdotal stories (some are very true) about the difficulty in gathering marketing's requirements when building a marketing database.
Because marketing constantly tries new ideas, tests results, and compares one group to another traditional requirements around 'what reports would you like to see' simply fails to capture the essence of the job. Instead, successful implementations base the design of the marketing database on the concepts of events and context.
Events are those marketing and customer activities that are relevant to executing and understanding the process. For example, this would include 'Contact', 'Request', 'Registration' etc. across channels. Start by listing all the specific events from the beginning of the customer journey to end.
Context is the information that helps marketing understand the 'who, what, when, and why'. For each event list all of the possible questions that need to be answered to fully comprehend a specific event.
A successful design allows a marketer to easily understand and talk about the events and context when segmenting, profiling or selecting people for campaigns.
Don't stop the exercise because 'that data isn't available' --- this is a logical problem first and foremost. A good design allows data to be added over time as required without restructuring the system.