Web Services Use and Reuse

In this era of when IT departments must meet strict measurements of return on investment (ROI), most companies want metrics to demonstrate that their SOA initiative is progressing and delivering value. So, how do you accurately quantify SOA value? Hint: Don't simply count the number of Web services. Pay close attention to the amount of Web services use and reuse you're racking up.

The Idea: "Our SOA Initiative is a Success: Just Look at All the Services We Have"

Rimstar Bank's executive board had requested a report on the value of its SOA initiative. The bank's CTO, however, was unsure how to quantify this value. Ultimately, he decided to base this figure on the total number of services that the IT team had developed and that were in production. The company had 25 services in production, with five being reused for multiple business processes.

Why It Wasn't So Smart

The primary business value provided by a SOA is reuse. The number of Web services therefore has nothing to do with the success of the SOA initiative. In fact, a high number of services can be a leading indicator that the initiative is a SOA failure - since it's likely that reuse is not happening.

At Rimstar Bank reuse was low, with 20 of the 25 services in production still being used as individual applications. Thus, existing applications being converted to services, or newly created services, were not the right ones to tally for an ROI report. After all, they were not being reused by any other applications and processes, nor were they being reused by other lines of business.

A Better Approach

When calculating the value of a SOA, it's best to focus on reuse among existing Web services, rather than the number of newly developed Web services. Reuse is not only a key benefit of SOA, but also something that you can quantify.

You can measure how many times a service is being used and how many processes it is supporting, thus the number of items being reused. This enables you to measure the value of the service. With a little work, you can calculate the service cost savings for each instance of reuse, including saved architecture and design time, saved development time, and saved testing time.

Web services reuse is everything: on top of the major cost saving mentioned above, reuse means there are fewer services to maintain and triage. So reuse generates savings – and frequency of use drives value in the organization.

For More Information

Discover why many believe Web services reuse is the holy grail of SOA: download the free webinar, Implementing a Successful SOA Pilot Program.