Great article. But I'd take it one step further. While automating a manually produced report that takes days if not weeks to produce might be the ultimate goal, a report could consist of information captured in multiple business processes from multiple systems. The danger of letting a report or a small set of reports guide your requirements is that you run the risk of creating a series of spreadsheet marts that each contain data that cannot be easily integrated. While gathering requirements, data sources need to be classified into two categories, business actor (dimensions) or business process (facts). And the Kimball data bus matrix (or SSAS cube editor Dimension Usage tab) needs to be the final product of the requirement gathering stage. From those results, the data warehouse can be constructed iteratively and incrementally, one source, one business actor, one business process at a time. And as the business changes, so will the data bus matrix.