One of the ways that companies test new product concepts is by building physical prototypes and letting users try them. Seenu Srinivasan, a Stanford Business School professor of marketing and management science, thinks that virtual prototypes created online might make more sense than physical prototypes for some companies. His research indicates that virtual prototypes provide nearly the same results as physical prototypes. He quickly adds that virtual prototypes are often much less expensive to build and test than their physical protocounterparts. "The Web reduces the uncertainty in new product introduction by allowing product testing of more ideas in parallel," says Srinivasan. He worked with a bicycle pump manufacture that compared a new pump design against competitive designs. They found that the virtual prototype worked as well as the physical prototypes when predicting which design would be most successful. However, Srinivasan also says virtual prototypes are not perfect. "It remains to be seen which goods are best suited to virtual visual testing." For more information, go to www.gsb.stanford.edu.