When considering the business case for SOA, most organizations seek benefits such as business agility, faster time to market, increased asset reuse, lower software maintenance, and reduced integration expense or legacy system consolidation. All great goals, but these desired SOA outcomes may fall victim to business case analysis. Consider the much-desired "business agility." How does an organization know it has become more agile? As measured how?
With SOA, the business case and ROI analysis can be tricky. I like to treat SOA as a series of ROI or value thresholds through which an organization progresses on its journey to desired business outcomes. SOA requires sustained investment toward creating reusable, composable services, which are leveraged to deliver value as they are consumed by various developers, internal and external customers, and trading partners. Once you have a portfolio of reusable services in place, you can begin to accrue more value by leveraging those assets.
