Enterprise architecture is the organizing logic for business processes and IT infrastructure reflecting the integration and standardization requireme… - Jeanne W. Ross

The insights in the book come from a series of research projects exploring enterprise architecture in more than 200 companies where our focus was on IT government from 1995 to 2005.

Assessing the value of information technology (IT) has never been easy. Delayed benefits, unintended uses, business changes, and hidden support costs inhibit meaningful evaluation of individual IT investments. This was true when most investments were focused on the support of a single business process or functional area. It is even more true as business executives ponder implementations of shared technologies like data warehouses and networks, replacement of large legacy systems, and reskilling of the IT staff. Although firms introduce some systems to reduce costs and can evaluate them in terms of their success in doing so, they want many IT initiatives to support a firm's objectives. The value of these initiatives rest in their contributions to a firm's competitiveness, which is often non quantifiable and uncertain.

IT architecture is often assumed to follow business strategy, to align IT with the business's strategic objectives. Increasingly, though, many business strategies depend on specific underlying IT capabilities. To develop a synergy between business strategy and IT architecture, firms must develop organizational competencies in IT architecture. My research has identified four IT architectural stages, each with its own requisite competencies. The "application silo architecture stage" consists of IT architectures of individual applications. The "standardized technology architecture stage" has an enterprise-wide IT architecture that provides efficiencies through technology standardization. The "rationalized data architecture stage" extends the enterprise-wide IT standards to data and processes. And the "modular architecture stage" builds onto enterprise-wide global standards with loosely coupled IT components to preserve the global standards while enabling local differences. Each stage demands different organizational competencies to implement the architecture and prepare the firm to move to the next stage.