Identifying and reducing
What is the best way to identify duplication? Start with creating an inventory of all software and systems (yes, surprisingly not every organization does this). Make sure this inventory crosses all silos of the organization. Do the follow-up, talk with all stakeholders responsible for software, infrastructure, and related licensing. Create a spreadsheet, diagram, database, or whatever works best for you to visualize all the software, systems, etc... make sure you have a good written description of each. Be sure you can discuss the diagram in a vocabulary that each stakeholder understands. If you can get a sense of cost associated with each, get that information... reach out to the help-desk to get information of which systems require the greatest support, look into the ongoing data entry (duplicate or otherwise) costs, find out how many simultaneous users each system has, gather licensing costs. With all this information you should be able to identify duplication across the silos and within the software features. There will be duplication that can be "easily" removed or licensing schemes that can be adjusted.
Regardless of the cost in doing all this work, it will be less than the savings collected from reduced duplication and over-subscribed licensing.
-- If you want assistance with this or similar IT architecture initiatives feel free to contact me;
Peter, the pragmatic architect.