Typically the overall IS strategy will envisage a combination of methods of operation with some functions being devolved, some decentralised, and some centralised. This is sometimes referred to as the 'build or buy' decision. The formulation of a technology architecture is typically an iterative process. A draft architecture is formulated. It is then evaluated and modified as often as is necessary to arrive at an appropriate architecture.
Many factors influence the choice of technical architecture for a given group of applications.
Other things being equal, cost will be one of the most important considerations. Some options will rule themselves out because of a lack personnel with the necessary technical expertise to implement and support the use of the technology. Certain technology architectures may require users to manage the technology used by them. Others can be managed by a central IS department. Making users responsible for managing their own systems can give users a greater sense of ownership of their systems.