The practice of enterprise architecture is about informing the business decision making process by understanding how complex organizations are structured, how they function, and what technology supports those functions. It must be recognized that, in most cases, increasing complexity in IT has been the driver for Enterprise Architecture adoption – the sudden increase in IT portfolio size that results from a merger or acquisition has often been identified as a justification for Enterprise Architecture projects. What it seeks to do is model the relationships between the business and technology in such a way that key dependencies are exposed from the underlying complexity and so can be used to support decisions. One could call this a critical path of dependencies between the operational domain and the technology. For example, by ascertaining which business processes are supported by a given software application, and then which platform the application runs on, it is possible to calculate the impact on the business of hardware obsolescence. From the same model, it would also be possible to examine the cost of replacing the application, or which processes could be best re-designed to reduce the IT portfolio. When other dimensions are introduced such as data models, organizational structure and standards, questions which initially appear impossibly convoluted can be answered, provided the dependencies between domains are all known. The information that is used to inform an Enterprise Architecture can often be obtained from the appropriate departments of the organization.