Table: Running the Numbers

Here's the skinny on the most common methods of assessing ROI:

Quick calculators: These are fill-in-the-blank forms, often on the Web sites of tech companies. Potential customers plug in facts about their business and get a ballpark estimate of how much they can save.

How useful: Because the formulas are so general, experts don't consider them to be reliable forecasts of savings.

Case studies: Tech outfits often trot out case studies of completed projects to try to persuade potential customers to buy their products.

How useful: Problem is, each company's situation is different.

ROI forecasts: Detailed info about a company's technology and business performance is collected and compared with results from its peers.

How useful: This is fairly reliable because it focuses on one company.

ROI assessments: These studies are done after a project is finished.

How useful: The approach is highly accurate. But because it's done after the fact, it doesn't help with buying decisions.

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