When you combine the list of EDW subject areas with the notion of conformed dimensions, a powerful diagram emerges, which we call the enterprise data warehouse bus matrix. A typical bus matrix is shown in following figure:
At the beginning of an EDW implementation, this bus matrix is very useful as a guide, both to prioritize the development of separate subject areas and to identify the potential scope of the conformed dimensions. The columns of the bus matrix are the invitation list to the conformed dimension design meeting.
Before the conformed dimension design meeting occurs, this bus matrix should be presented to senior management, perhaps in exactly the form of above Figure . Senior management must be able to visualize why these dimensions (master entities) attach to the various business process subject areas, and they must appreciate the organizational challenges of assembling the diverse interest groups together to agree on the conformed dimension content. If senior management is not interested in what the bus matrix implies, then, to make a long story short, you have no hope of building an integrated EDW.
It is worth repeating the definition of a conformed dimension at this point to take some of the pressure off of the conforming challenge. Two instances of a dimension are conformed if they contain one or more common fields, whose contents are drawn from the same domains. This means that the individual subject area proponents do not have to give up their cherished private descriptive attributes. It merely means that a set of master, universally agreed-upon attributes must be established. These master attributes then become the contents of the conformed dimension and become the basis for drilling across.
the bus matrix can be viewable from BIDS using SSAS project in dimension usage tab.