Trying to determine if usability results in positive ROI ...
"Consider this true story. As product manager flew overseas to demonstrate his ground-breaking software application to an executive team in a multi-billion dollar company. Halfway into his demonstration, he got lost in the application’s interface and could not navigate his way out. The executives dismissed him, with an admonition to go back and fix his problems.
For years, interface gurus have hotly debated the value of an application interface in term of return on investment. How much influence does usability have on an application’s ROI? Can a great interface possibly justify its expense? The answer is yes. Forward-thinking companies are finally realizing the importance of usability. “Usability is one of our secret weapons,” says a representative from Schwab.com. The fact that usability consistently produces positive results will not be a secret much longer.
A case in point: American Eagle Outfitters launched a redesigned, more user-centered Web site in March, 2001, and showed a 53.6% increase in sales the next month. Can that increase be directly attributed to usability? Usability research is limited in its ability to predict ROI simply because there are too many variables, leaving decision-makers skeptical of usability expenses.
Usability guru Jakob Nielsen argues that starting with usability is key to increasing ROI. He estimates that gathering usability data early in the development process is ten times more effective than late usability data. “It's 100 times cheaper to make a change before any code has been written than it is to wait until after the implementation is complete,” he states, but admits that such estimates do not equate to a standard ROI. “The two parameters are measured in different units,” he argues, “Project cost is measured in money, and usability is measured in increased use, more efficient use, or high user satisfaction."
continued ... (Via PRWeb) 
Return On Investment.