Nicholas Carr caused quite a stir back in May when he distributed his thoughts on why \u201cIT Doesn\u2019t Matter." Since the release of Carr\u2019s article in the Harvard Business Review, industry analysts and enterprise network managers have been working to prove just how much IT supports business - more importantly, how IT makes business perform better.In a recent report, \u201cWhy Performance Management Matters,\u201d Jim Metzler, co-founder of IT Business Media, explains how performance management and network optimization can provide measurable competitive advantages to individual units within a company. Metzler says business unit managers usually perceive the applications they use to be more important than the network that supports them.\u201cRegrettably, it can be extremely difficult to demonstrate this linkage\u201d between apps and networks, Metzler says in the report.For this reason, IT managers need to demonstrate how an optimized network delivers better-performing applications. They have to make the link between the business service and the infrastructure supporting it clear to business units.Take Wendy Welsh. The senior vice president of IT at Louisville Gas & Electric Energy in Kentucky says the best way to push IT projects through the budget process is to find that business unit manager willing to back new technology.\u201cYou need to make investments in IT from a business standpoint,\u201d Welsh says.To make the business case for IT, Welsh recommends that enterprise IT managers practice IT governance as a means to keep technology spending and labor costs under control. At her organization, they rotate PCs for their 4,000 end users out every three years, no matter what their condition. That policy resulted from a process that proved that the ongoing maintenance, support and labor required for keeping older infrastructure around exceeded the cost of rolling out new hardware periodically.After setting rules and priorities for IT governance based on business demands, Welsh says IT managers must measure IT to prove its worth.\u201cWe make sure we are not taking technology solutions and running around looking for a problem to solve with the new technology,\u201d Welsh says. \u201cWe find the business drive first, put policies in place, measure the results and prove the technology\u2019s value.\u201dNext time: More on why performance management matters, and how enterprise network managers make their case.