Los Angeles--About 38% of b-to-b e-marketplace executives interviewed for a recent survey said that low traffic is one of the biggest reasons hubs fail, according to a new survey released at the Ground Zero conference. More than 18%, meanwhile, said that flawed business plans are another reason for failure. Only 6% said marketing research is critical to a b-to-b e-hub succeeding, according to the survey, prepared by Pittsburgh-based consultancy eMarket Concepts. Notably, 56% of the executives polled said b-to-b marketplaces fail to complete usability testing before going live. And only 46% said domain expertise is key to success. Thirty-four b-to-b e-marketplace executives were interviewed for the survey. The interviews were held in October and November.