At UBS, Abbey says, "we start with a view of the desired outcomes for each of the businesses, then derive from that an overall technology strategy that we can test with benchmarks to see if we've got out of it what we expected and to understand that if that was or wasn't the case". Even if Rubin's research improves a CIO's ability to understand his spending's impact on business performance, achieving efficiency should not be ignored, says Gartner's Howe. "Finding each dollar through increased efficiency is still a worthy cause," he says. "You can spend those dollars for whatever has the best return, whether that's in IT or not."

Separate research at the BTM Institute, an industry think tank, reinforces the idea that smart technology management is essential to getting the desired return on IT investments. Its research shows that companies that treat IT as a driver of business growth get better financial performance and "that doesn't necessarily mean they're spending more on technology", says Faisal Hoque, the institute's chairman.

Other research shows that companies that have managed the complexity of their IT by building well-conceived systems rather than throwing a lot of technology at the wall to see what sticks get higher value from their IT spend, notes PricewaterhouseCoopers's Zukis.

At the end of the day, there's no magic formula to justify IT budgets, no wand to wave that guarantees that real business value will pop out of the technology investment hat. But good CIOs shouldn't be looking for magic, says Rubin. They should be using their skills in the science and art of IT to manage technology as the critical investment it is.

"The CIO," concludes Rubin, "is a fund manager who needs to get the right return on his investment for the risk assumed - and who must make sure his portfolio is managed well."