Imagine the information flow through the business units of an organization as a connected network of nodes. Each edge in the graph represents some type of process (automated or manual) that moves information from one department to another. The Information Supply Chain model describes how each of those edges has a cost associated with it. Each edge, to be worth while, must also create some added value (either through reduced effort via automation or added meaning). The cost / benefit sides of those edges, though, don't typically come from / contribute to the same departmental bottom line. Typically it is a matter of the originating business unit paying the cost of additional data collection or manipulation so that a receiving business unit can benefit.
In the VERY simple diagram above, the argument is obvious. The Admitting department in a hospital has the purpose of collecting information from a patient that other departments will need in order to do their job effectively. Admitting collects patient information (e.g. contact information, primary care physician, insurance information) once so that other departments can all benefit from it. Surgery uses the information collected during Admitting to retrieve the patient's medical record and orders. Billing uses the same patient information plus the additional information about what procedures were performed by Surgery to create invoices to payers (who will use similar information to try to avoid paying the bills).
It would be inefficient if the Surgery department had to collect from you the information it needs to find your medical record and orders; then have your surgical procedure followed immediately by a visit from the billing department to collect the same information about you so that they could proceed with coding and billing processes. This clearly does happen sometimes. Occasionally with good cause, but often because of redundancies between systems, and sometimes because the process doesn't think to collect a piece of information up front. For instance, Admitting may not have any reason to ask "do you have any allergies" because that isn't necessary to complete their assignment of "log that the patient arrived and notify surgery." So, Surgery has to ask the additional questions that are important to it "have you eaten," "do you have any allergies," etc. With some of those questions, significant time and safety risks could be avoided if they are asked as early in the encounter as possible.
So, it seems to me that Enterprise Information Management is most importantly about the management of the edges of that graph and has a direct impact on the efficiency of the Information Supply Chain. Those edges between the nodes of the diagram aren't merely straight lines that magically move information from one business process to another. They are interfaces and systems and business processes that cost significant time, money, and risk to quality.
Why can't we expect each business unit to simply do what will result in an optimal collection and movement of information? Not because they're maliciously selfish about their time or resources, but because individual business units don't usually have the perspective to fully understand the down stream value of their own operations. Enterprise Information Management is the work that lives in between business units and drives overall optimization of the edges between them. Enterprise Information Management is something that lives between and outside of individual business units. Business units can be counted on to optimize their own internal operations. Enterprise Information Management has to be planned and managed explicitly, above and beyond departmental objectives.
