Wal-Mart Stores is on a mission to determine the social and environmental impact of every item it puts on its shelves. And it has recruited scholars, suppliers, and environmental groups to help it create an electronic indexing system to do that... “Nobody else could pull this off,” said Michelle Harvey at Environmental Defense Fund, one of the groups involved in the creation of the index... Joe Cavaliere, a senior vice president for customer development at Unilever, a big Wal-Mart supplier, called the indexing idea “a great move forward for the industry.”... Procter & Gamble said sharing the new sustainability index across the industry was important.