Business schools are putting Wal-Mart's sustainability and responsibility practices under the microscope in order to train the next generation of responsible business leaders. Students take a clear-eyed look both at Wal-Mart's green-business successes and ethical missteps, says David Hyatt of the Walton College of Business in Arkansas. "We are not presuming that Wal-Mart is setting best practices," he says. "The important questions become, 'How would students have gone about doing this?' and How do you begin to measure progress?' "