The detailed analysis helped L'Hereux choose the right package, of course, but it had a side benefit as well, he says. "It's an exercise for the people who will use the system to understand what it will do and what they want it to do," he says.

That exercise can head off unpleasant user scenarios. "They all want everything, but when they get it, they don't want to use it because it doesn't work like the old way," L'Hereux says. Or another unwanted user reaction: "Bring it in, and then I'll tell you why I don't want it," he says.

Like Boeing, Rockford Health relies on market research to provide some guidance. L'Hereux taps into the analyses of Klas Enterprises LLC, an IT product research firm for the health care industry, to help him prescreen products and vendors.

L'Hereux says it was once standard practice for IT shops to put together "very detailed requests for proposals in three-ring binders with everything we wanted in a system." But in addition to being time-consuming and costly, he says, that process "doesn't materially result in any better decision."

Indeed, says MIT's Grochow, spending a lot of time on an IT buy is no guarantee of success. "People will say, 'Let's examine the details of all 30 alternatives.' Do they come up with a significantly better decision than the person who says, 'Here are the two market leaders; let's bring one of them in here and try it'?"