We define data change rules using our Natural Language approach to transform the data from the raw state you provided, to a format that can be used to easily and repeatably answer your question.  This may include simple rules such as which data identifies a unique customer, or complex rules, for example, deriving a single (golden) customer record from multiple disparate sets of customer data.

We do the majority of the effort defining these, but your time is needed to help us review them.