Vendors produce sparkling accounts of how their software or service reaps huge benefits, quickly. They have wonderful ROI calculations, in other words, not to mention persuasive charts and figures. But, take it all with a shaker of salt.
Even so, it is smart to work jointly with a vendor to let them help you craft what you view to be a measured calculation of the benefit to be gained by a proposed investment. You can use some help to clear the hurdles set by finance (See my post of Oct. 22, 2008: ROI with 17 references.). Vendors will oblige